 
     
      
      
      
    | Length of shell (after assembly) | 33.5mm (excl. the plug) | 
| Weight | 4.0g (BM25) | 
| 4.1g (BM35) | |
| 5.1g (BM44) | |
| Material of plug | High purity 24K gold-plated copper | 
| Internal connecting material | Mixed conductor of OCC and silver-plated OCC | 
| Material of shell | 6063 aluminium alloy |