- 
        Signature
      
 
      - 
        /s/Michelle R. Mekinda, as Attorney-In-Fact
      
 
    
    
      
- 
        Stock symbol
      
 
      - 
        MTRN
      
 
    
    
      
- 
        Transactions as of
      
 
      - 
        Mar 11, 2022
      
 
    
    
      
- 
        Transactions value $
      
 
      - 
        $0
      
 
    
    
      
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        Form type
      
 
      - 
        4
      
 
    
    
      
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        Date filed
      
 
      - 
        3/15/2022, 03:40 PM
      
 
    
    
    
    
   
     
   
 
  
    Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)
  
  
    
      
        
          | Type | 
          Sym | 
          Class | 
          Transaction | 
          Value $ | 
          Shares | 
          Change % | 
          * Price $ | 
          Shares After | 
          Date | 
          Underlying Class | 
          Amount | 
          Exercise Price | 
          Ownership | 
          Footnotes | 
        
      
      
          
            | transaction | 
            MTRN | 
            Restricted Stock Units | 
            Award | 
            $0 | 
            +2 | 
            +0.16% | 
            $0.00 | 
            1.25K | 
            Mar 11, 2022 | 
            Common Stock | 
            2 | 
             | 
            Direct | 
            F1, F2, F3 | 
          
      
    
   
  
    * An asterisk sign (*) next to the price indicates that the price is likely invalid.
  
  
    Explanation of Responses:
  
  
  
    Remarks:
  
  Exhibit 24 Power of Attorney