Exhibit 21

SUBSIDIARIES OF PRECISION CASTPARTS CORP.

|Name of Subsidiary                            |  | Approximate
Percentage of Voting
Securities Owned |  | State or Jurisdiction
of Incorporation or
Organization
|--------------------------------------------- |  | ------------------------------------------------- |  | ------------------------------------------------------
|                                             
|AAA Aircraft Supply LLC                       |  | 84.25%                                            |  | Delaware                                              
|Advanced Forming Technology, Inc.             |  | 100.0%                                            |  | Colorado                                              
|AETC Limited                                  |  | 100.0%                                            |  | United Kingdom                                        
|AFT Europa-Advanced Forming Technologies Ltd. |  | 100.0%                                            |  | Hungary                                               
|Air Industries Corporation                    |  | 100.0%                                            |  | California                                            
|ATAAS LLC                                     |  | 100.0%                                            |  | Delaware                                              
|Avibank Mfg., Inc                             |  | 100.0%                                            |  | Delaware                                              
|Avibank Services LLC                          |  | 85.0%                                             |  | Delaware                                              
|Cannon-Muskegon Corporation                   |  | 100.0%                                            |  | Michigan                                              
|CW Valves Services Co.                        |  | 100.0%                                            |  | Texas                                                 
|Cypress Extrusion Press Corporation           |  | 100.0%                                            |  | Delaware                                              
|Environment-One Corporation                   |  | 100.0%                                            |  | New York                                              
|FRISA Wyman-Gordon LLC                        |  | 51.0%                                             |  | Delaware                                              
|FRISA Wyman-Gordon, S.A. de C.V.              |  | 51.0%                                             |  | Mexico                                                
|Greenville Metals, Inc.                       |  | 100.0%                                            |  | Pennsylvania                                          
|Greer Stop Nut, Inc.                          |  | 100.0%                                            |  | Tennessee                                             
|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 LTD                  |  | 50.0%                                             |  | India                                                 
|M. Argueso & Company, LLC                     |  | 100.0%                                            |  | Delaware                                              
|Magnetstuff.com, Inc.                         |  | 100.0%                                            |  | Illinois                                              
|Mecair Aerospace Industries, Inc.             |  | 100.0%                                            |  | Canada                                                
|Melcut Tools, Inc.                            |  | 100.0%                                            |  | South Carolina                                        
|Melcut Tools, Ltd                             |  | 100.0%                                            |  | Ireland                                               
|Metalac Fasteners, Inc.                       |  | 100.0%                                            |  | Illinois                                              
|Metalac S/A Industria e Comercio              |  | 100.0%                                            |  | Brazil                                                
|Metalac SPS Industria e Comercio, Ltda        |  | 100.0%                                            |  | Brazil                                                
|Mohawk Cutting Tools Sales, Ltd               |  | 100.0%                                            |  | United Kingdom                                        
|Mohawk Ueopa, Ltd                             |  | 100.0%                                            |  | Ireland                                               
|Non-Ferrous Bolt & Manufacturing Co           |  | 100.0%                                            |  | Nevada                                                
|NSS Technologies, Inc.                        |  | 100.0%                                            |  | Michigan                                              
|Oregon Plasma                                 |  | 50.0%                                             |  | Oregon                                                
|Otto Vogeli Industriearmaturen GmbH           |  | 100.0%                                            |  | Germany                                               
|PCC Airfoils S.A. de C.V.                     |  | 100.0%                                            |  | Mexico                                                
|PCC Airfoils, LLC                             |  | 100.0%                                            |  | Ohio                                                  
|PCC Composites, inc.                          |  | 100.0%                                            |  | Colorado                                              
|PCC Flow Technologies (Switzerland) 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 Luxembourg Holdings LLC                   |  | 100.0%                                            |  | Delaware                                              
|PCC Luxembourge Holdings SCS                  |  | 100.0%                                            |  | Luxembourg                                            
|PCC Specialty Products, Inc.                  |  | 100.0%                                            |  | Delaware                                              
|PCC Structurals, Inc.                         |  | 100.0%                                            |  | Oregon                                                
|PCC Valves & Controls, Inc (formerly TBV)     |  | 100.0%                                            |  | Delaware                                              
|PCC Wouter Witzel Holding B.V.                |  | 100.0%                                            |  | Netherlands                                           
|PCC Wouter Witzel Ltd.                        |  | 100.0%                                            |  | United Kingdom                                        
|Precision Castparts Aviation, Inc.            |  | 100.0%                                            |  | Oregon                                                
|Precision Castparts Corp. France, S.a.r.l.    |  | 100.0%                                            |  | France                                                
|Precision Castparts CZ s.r.o.                 |  | 100.0%                                            |  | Czech Republic                                        
|Precision Founders, Inc.                      |  | 100.0%                                            |  | California                                            
|Precision Receivables Corp.                   |  | 100.0%                                            |  | Oregon                                                
|S.M.T., Ltd                                   |  | 100.0%                                            |  | Ireland                                               
|S.P.S. International Limited                  |  | 100.0%                                            |  | Ireland                                               
|SPS Aerostructures Limited                    |  | 100.0%                                            |  | United Kingdom                                        
|SPS Asia Ltd.                                 |  | 100.0%                                            |  | Hong Kong                                             
|SPS Chevron Limited                           |  | 100.0%                                            |  | United Kingdom                                        
|SPS Hi-Tek, Ltd                               |  | 100.0%                                            |  | Ireland                                               
|SPS International Investment Co               |  | 100.0%                                            |  | Delaware                                              
|SPS International, S.a.R.L.                   |  | 100.0%                                            |  | Luxembourg                                            
|                                              |  |                                                   |  |                                                       

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|SPS Malta Limited                              |  | 100.0% |  | Malta         
|---------------------------------------------- |  | ------ |  | --------------
|SPS Pacific Limited                            |  | 100.0% |  | Malta         
|SPS Tech Trading Limited                       |  | 100.0% |  | United Kingdom
|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 Trading Pte., Ltd             |  | 100.0% |  | Singapore     
|SPS Technologies Waterford Company             |  | 100.0% |  | Michigan      
|SPS Technologies, LLC                          |  | 100.0% |  | Pennsylvania  
|SPS/Unbrako K.K.                               |  | 100.0% |  | Japan         
|Standco Canada, Ltd                            |  | 100.0% |  | Canada        
|STW Composites, Inc.                           |  | 100.0% |  | Delaware      
|Swift Levick Magnets Limited                   |  | 100.0% |  | United Kingdom
|T.J. Brooks, Ltd.                              |  | 100.0% |  | United Kingdom
|Technova GmbH                                  |  | 100.0% |  | Germany       
|The Arnold Engineering Co.                     |  | 100.0% |  | Illinois      
|Unbrako LLC                                    |  | 100.0% |  | Delaware      
|Unbrako Mexicana SRL de C.V.                   |  | 100.0% |  | Mexico        
|Unbrako Schrauben, GmbH                        |  | 100.0% |  | Germany       
|Unbrako, Inc.                                  |  | 100.0% |  | Delaware      
|Unrako Products (Singapore), Ltd.              |  | 100.0% |  | Singapore     
|Unrako Pty., Ltd.                              |  | 100.0% |  | Australia     
|Western Australian Specialty Alloys, Pty. Ltd. |  | 100.0% |  | Australia     
|Wyman Gordon (Cleveland), Inc.                 |  | 100.0% |  | Ohio          
|Wyman Gordon EG S. de R.L. de C.V.             |  | 50.1%  |  | Mexico        
|Wyman-Gordon Company                           |  | 100.0% |  | Massachusetts 
|Wyman-Gordon de Mexico S. de R.L. de C.V.      |  | 100.0% |  | Mexico        
|Wyman-Gordon Forgings LP                       |  | 100.0% |  | Delaware      
|Wyman-Gordon Investment Castings, Inc.         |  | 100.0% |  | Delaware      
|Wyman-Gordon Limited                           |  | 100.0% |  | United Kingdom
|Wyman-Gordon s.r.o.                            |  | 100.0% |  | Czech Republic
|Wyman-Gordon Washington Street, LLC            |  | 100.0% |  | Delaware      
|300 N West Street LLC                          |  | 100.0% |  | Delaware      
|                                              

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