Exhibit 21

SUBSIDIARIES OF PRECISION CASTPARTS CORP.



|                                               |  |                                                 |   |  |                                                     
|---------------------------------------------- |  | ----------------------------------------------- | - |  | ----------------------------------------------------
|Name of Subsidiary                             |  | ApproximatePercentage of VotingSecurities Owned |   |  | State or Jurisdictionof Incorporation orOrganization
|AAA Aircraft Supply LLC                        |  | 83.25                                           | % |  | Delaware                                            
|Advanced Forming Technology, Inc.              |  | 100.0                                           | % |  | Colorado                                            
|AETC Limited                                   |  | 100.0                                           | % |  | United Kingdom                                      
|AFT Europa-Advanced Forming Technology Limited |  | 100.0                                           | % |  | Hungary                                             
|Alexander Socket Screws Limited                |  | 100.0                                           | % |  | United Kingdom                                      
|ATAAS LLC                                      |  | 100.0                                           | % |  | Delaware                                            
|Avibank Mfg., Inc                              |  | 100.0                                           | % |  | Delaware                                            
|Avibank Services LLC                           |  | 85.0                                            | % |  | Delaware                                            
|BI, Inc.                                       |  | 100.0                                           | % |  | Canada                                              
|Cameron Forged Products, Limited               |  | 100.0                                           | % |  | United Kingdom                                      
|Cannon-Muskegon Corporation                    |  | 100.0                                           | % |  | Michigan                                            
|Carmet Company                                 |  | 100.0                                           | % |  | South Carolina                                      
|Carmet Investors, Inc.                         |  | 100.0                                           | % |  | Georgia                                             
|Chevron Aerospace Group, Limited               |  | 100.0                                           | % |  | United Kingdom                                      
|Chevron Aerostructures, Limited                |  | 100.0                                           | % |  | United Kingdom                                      
|Columbia Steel Equipment Company               |  | 100.0                                           | % |  | Pennsylvania                                        
|Cypress Extrusion Press Corporation            |  | 100.0                                           | % |  | Delaware                                            
|Environment-One Corporation                    |  | 100.0                                           | % |  | New York                                            
|Fabricas Non-Ferrous S.A. de C.V.              |  | 100.0                                           | % |  | Mexico                                              
|Flow Tech Realty Co.                           |  | 100.0                                           | % |  | Delaware                                            
|FRISA Wyman-Gordon LLC                         |  | 51.0                                            | % |  | Delaware                                            
|FRISA Wyman-Gordon, S.A. de C.V.               |  | 51.0                                            | % |  | Mexico                                              
|General Valve Company Limited                  |  | 100.0                                           | % |  | United Kingdom                                      
|General Valve of Canada, Inc.                  |  | 100.0                                           | % |  | Canada                                              
|Green Penny Company                            |  | 100.0                                           | % |  | Delaware                                            
|Greer Stop Nut, Inc.                           |  | 100.0                                           | % |  | Tennessee                                           
|Greenville Metals, Inc.                        |  | 100.0                                           | % |  | Pennsylvania                                        
|Hallowell, Inc.                                |  | 100.0                                           | % |  | Delaware                                            
|Hi-Life Tools (UK) Limited                     |  | 100.0                                           | % |  | United Kingdom                                      
|Hi-Life Tools France, E.U.R.L.                 |  | 100.0                                           | % |  | France                                              
|Hi-Life ULMA, Srl                              |  | 100.0                                           | % |  | Italy                                               
|Howell Penncraft, Inc.                         |  | 100.0                                           | % |  | Delaware                                            
|J&L Fiber Services, Inc.                       |  | 100.0                                           | % |  | Wisconsin                                           
|Kadimi Tool Mfg. Co. PVT Limited               |  | 50.0                                            | % |  | India                                               
|Kasar Manufacturing & Distributing Co., Inc.   |  | 100.0                                           | % |  | California                                          
|M. Argueso & Company, LLC                      |  | 100.0                                           | % |  | Delaware                                            
|Magnetstuff.com, Inc.                          |  | 100.0                                           | % |  | Illinois                                            
|Mecair Aerospace Industries, Inc.              |  | 100.0                                           | % |  | Canada                                              
|Metalac Fasteners, Inc.                        |  | 100.0                                           | % |  | Illinois                                            
|Metalac S.A. Industria e Commercio             |  | 100.0                                           | % |  | Brazil                                              
|Metalac SPS Industria e Commercio, Ltda        |  | 100.0                                           | % |  | Brazil                                              
|Mohawk Cutting Tools Sales, Limited            |  | 100.0                                           | % |  | United Kingdom                                      
|Mohawk Europa, Limited                         |  | 100.0                                           | % |  | Ireland                                             
|Non-Ferrous Bolt & Manufacturing Co            |  | 100.0                                           | % |  | Nevada                                              
|Northland Avenue Properties, LLC               |  | 100.0                                           | % |  | Delaware                                            
|NSS Technologies, Inc.                         |  | 100.0                                           | % |  | Michigan                                            
|Nutt-Shell Company                             |  | 100.0                                           | % |  | California                                          
|Oregon Plasma                                  |  | 50.0                                            | % |  | Oregon                                              



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|                                                  |  |       |   |  |               
|------------------------------------------------- |  | ----- | - |  | --------------
|Otto Vogeli Industriearmaturen GmbH               |  | 100.0 | % |  | Germany       
|PCC Airfoils S.A. de C.V.                         |  | 100.0 | % |  | Mexico        
|PCC Airfoils, LLC                                 |  | 100.0 | % |  | Ohio          
|PCC Business Trust                                |  | 100.0 | % |  | Delaware      
|PCC Composites, Inc.                              |  | 100.0 | % |  | Colorado      
|PCC CZ s.r.o.                                     |  | 100.0 | % |  | Czech Republic
|PCC European Holdings Sarl                        |  | 100.0 | % |  | Luxembourg    
|PCC European Luxembourg Holdings SCS              |  | 100.0 | % |  | Luxembourg    
|PCC Eurovalve B.V.                                |  | 100.0 | % |  | Netherlands   
|PCC Finance Luxembourg Sarl                       |  | 100.0 | % |  | Luxembourg    
|PCC Flow Technologies AG                          |  | 100.0 | % |  | Switzerland   
|PCC Flow Technologies Holdings, Inc.              |  | 100.0 | % |  | Delaware      
|PCC Flow Technologies Limited                     |  | 100.0 | % |  | United Kingdom
|PCC Flow Technologies LP                          |  | 100.0 | % |  | Delaware      
|PCC Flow Technologies Penberthy Canada, Inc.      |  | 100.0 | % |  | Delaware      
|PCC France, S.a.r.l.                              |  | 100.0 | % |  | France        
|PCC FT I LLC                                      |  | 100.0 | % |  | Delaware      
|PCC FT II LLC                                     |  | 100.0 | % |  | Delaware      
|PCC FT III LLC                                    |  | 100.0 | % |  | Delaware      
|PCC Luxembourg Holdings LLC                       |  | 100.0 | % |  | Delaware      
|PCC Specialty Products, Inc.                      |  | 100.0 | % |  | Delaware      
|PCC Structurals, Inc.                             |  | 100.0 | % |  | Oregon        
|PCC Wouter Witzel B.V.                            |  | 100.0 | % |  | Netherlands   
|PCC Wouter Witzel Eurovalve B.V.                  |  | 100.0 | % |  | Netherlands   
|PCC Wouter Witzel GmbH                            |  | 100.0 | % |  | Germany       
|PCC Wouter Witzel Holding B.V.                    |  | 100.0 | % |  | Netherlands   
|PCC Wouter Witzel Limited                         |  | 100.0 | % |  | United Kingdom
|PCC Wouter Witzel Specials B.V.                   |  | 100.0 | % |  | Netherlands   
|PCC Wouter Witzel Unit I B.V.                     |  | 100.0 | % |  | Netherlands   
|PCC Wouter Witzel Unit II B.V.                    |  | 100.0 | % |  | Netherlands   
|Precision Castparts Aviation, Inc.                |  | 100.0 | % |  | Oregon        
|Precision Founders, Inc.                          |  | 100.0 | % |  | California    
|Precision Receivables Corp.                       |  | 100.0 | % |  | Oregon        
|Reisner Metals, Inc.                              |  | 100.0 | % |  | California    
|Schulz Wo GmbH                                    |  | 100.0 | % |  | Germany       
|Shur-Lok International                            |  | 100.0 | % |  | Belgium       
|S.M.T., Limited                                   |  | 100.0 | % |  | Ireland       
|SPS Aerostructures Limited                        |  | 100.0 | % |  | United Kingdom
|SPS Asia Limited                                  |  | 100.0 | % |  | Hong Kong     
|SPS Chevron Limited                               |  | 100.0 | % |  | United Kingdom
|SPS (China) Co., Limited                          |  | 100.0 | % |  | China         
|SPS Hi-Tek, Limited                               |  | 100.0 | % |  | Ireland       
|SPS International                                 |  | 100.0 | % |  | Taiwan        
|SPS International Investment Co                   |  | 100.0 | % |  | Delaware      
|SPS International Limited                         |  | 100.0 | % |  | Ireland       
|SPS International S.a.r.l.                        |  | 100.0 | % |  | Luxembourg    
|SPS International Trading (Shanghai) Co., Limited |  | 100.0 | % |  | Netherlands   
|SPS Malta Limited                                 |  | 100.0 | % |  | Malta         
|SPS Pacific Limited                               |  | 100.0 | % |  | Malta         
|SPS Technologies Foreign Sales Corp.              |  | 100.0 | % |  | Barbados      
|SPS Technologies France, S.a.r.l.                 |  | 100.0 | % |  | France        
|SPS Technologies Limited                          |  | 100.0 | % |  | United Kingdom
|SPS Technologies LLC                              |  | 100.0 | % |  | Pennsylvania  
|SPS Technologies Overseas Holding B.V.            |  | 100.0 | % |  | Netherlands   



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|                                                  |  |       |   |  |               
|------------------------------------------------- |  | ----- | - |  | --------------
|SPS Technologies Trading Limited                  |  | 100.0 | % |  | United Kingdom
|SPS Technologies Trading Pte., Limited            |  | 100.0 | % |  | Singapore     
|SPS Technologies Waterford Company                |  | 100.0 | % |  | Michigan      
|SPS Unbrako K.K.                                  |  | 100.0 | % |  | Japan         
|Standco Canada, Limited                           |  | 100.0 | % |  | Canada        
|STW Composites, Inc.                              |  | 100.0 | % |  | Delaware      
|T.J. Brooks, Limited                              |  | 100.0 | % |  | United Kingdom
|Technova GmbH                                     |  | 100.0 | % |  | Germany       
|The Cleveland Cap Screw Company                   |  | 100.0 | % |  | Ohio          
|Unbrako, Inc.                                     |  | 100.0 | % |  | Delaware      
|Unbrako Limited                                   |  | 100.0 | % |  | United Kingdom
|Unbrako LLC                                       |  | 100.0 | % |  | Delaware      
|Unbrako Mexicana S.A. de C.V.                     |  | 100.0 | % |  | Mexico        
|Unbrako Products (Singapore), Limited             |  | 100.0 | % |  | Singapore     
|Unbrako Pty., Limited                             |  | 100.0 | % |  | Australia     
|Unbrako Schrauben, GmbH                           |  | 100.0 | % |  | Germany       
|Western Aerospace Limited                         |  | 100.0 | % |  | Australia     
|Western Australian Specialty Alloys, Pty. Limited |  | 100.0 | % |  | Australia     
|Wyman Gordon (Cleveland), Inc.                    |  | 100.0 | % |  | Ohio          
|Wyman-Gordon Company                              |  | 100.0 | % |  | Massachusetts 
|Wyman-Gordon Composites Technologies, Inc.        |  | 100.0 | % |  | California    
|Wyman-Gordon de Mexico S. de R.L. de C.V.         |  | 100.0 | % |  | Mexico        
|Wyman-Gordon Forgings LP                          |  | 100.0 | % |  | Delaware      
|Wyman-Gordon Forgings I LLC                       |  | 100.0 | % |  | Delaware      
|Wyman-Gordon Forgings II LLC                      |  | 100.0 | % |  | Delaware      
|Wyman-Gordon Forgings III LLC                     |  | 100.0 | % |  | Delaware      
|Wyman-Gordon Investment Castings, Inc.            |  | 100.0 | % |  | Delaware      
|Wyman-Gordon Limited                              |  | 100.0 | % |  | United Kingdom
|Wyman-Gordon (Lincoln) Limited                    |  | 100.0 | % |  | United Kingdom
|Wyman Gordon Monterrey S. de R.L. de C.V.         |  | 100.0 | % |  | Mexico        
|Wyman-Gordon Receivables Corp.                    |  | 100.0 | % |  | Delware       
|Wyman-Gordon s.r.o.                               |  | 100.0 | % |  | Czech Republic
|Wyman-Gordon SC, Inc.                             |  | 100.0 | % |  | California    
|Wyman-Gordon Washington Street, LLC               |  | 100.0 | % |  | Delaware      
|Vent-Tek Designs LLC                              |  | 50.0  | % |  | Delaware      
|300 N West Street LLC                             |  | 100.0 | % |  | Delaware