Exhibit 21.1

List of Material Subsidiaries



|                                                     |  |              |   |  |                             
|---------------------------------------------------- |  | ------------ | - |  | ----------------------------
|Subsidiary                                           |  | % Ownership1 |   |  | Jurisdiction ofIncorporation
|National Tank Company                                |  | 100          | % |  | Delaware                    
|NTC Technical Services, Inc.                         |  | 100          | % |  | Delaware                    
|Linco-Electromatic, Inc.                             |  | 100          | % |  | Texas                       
|NATCO Canada, Limited                                |  | 100          | % |  | Alberta, Canada             
|NTG Group de Mexico, S. de R.L. de C.V.              |  | 100          | % |  | Mexico                      
|NATCO Japan Company, Limited                         |  | 60           | % |  | Japan                       
|NATCO Group de Venezuela, S.A.                       |  | 100          | % |  | Venezuela                   
|NATCO Luxembourg S.a.r.l.                            |  | 100          | % |  | Luxembourg                  
|NATCO Norge Holdings AS                              |  | 100          | % |  | Norway                      
|NATCO Norway AS                                      |  | 100          | % |  | Norway                      
|Total Engineering Services Team, Inc.                |  | 100          | % |  | Louisiana                   
|TEST Angola Tecnologia e Serviços Petrolíferos, Lda. |  | 49           | % |  | Angola                      
|TEST Automation & Controls, Inc.                     |  | 100          | % |  | Louisiana                   
|TEST Nigeria, Limited                                |  | 100          | % |  | Nigeria                     
|TEST International                                   |  | 100          | % |  | Cayman Islands              
|Axsia Holdings Limited                               |  | 100          | % |  | UK                          
|Axsia Group Limited                                  |  | 100          | % |  | UK                          
|Axsia Limited                                        |  | 100          | % |  | UK                          
|NATCO UK Limited                                     |  | 100          | % |  | UK                          
|Axsia Howmar Limited                                 |  | 100          | % |  | UK                          
|Fluid Processing (Labuan) BHD                        |  | 100          | % |  | Malaysia                    
|Richard Mozley Limited                               |  | 100          | % |  | UK                          
|SureFire Pilotless Burner Systems LLC                |  | 50           | % |  | Delaware                    
|NTC Technical Services SDN BHD                       |  | 100          | % |  | Malaysia                    
|Western Measurement Equipment Co.                    |  | 100          | % |  | Colorado                    
|Scomi-NTC Sdn Bhd                                    |  | 30           | % |  | Malaysia                    



|1 | Represents ownership on a consolidated basis.
|- | ---------------------------------------------