Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series AEGs AK74U Y&P or STTI MK23 magazines

Y&P or STTI MK23 magazines

Steel construction

M4 magazine NOT included

FN Herstal

Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series AEGs AK74U Y&P or STTI MK23 magazinesUnlike most other gearbox shells on the market, the Retro Arms CZ gearbox shells are precision CNC machined out of a solid block of billet EN AW 7075 T651 aluminum giving them unmatched durability and resilience. Combined with reinforcement of key stress points and stainless steel connecting bolts, the gearbox shell has undergone extensive stress tests with M160 springs without any signs of wear. Precision machined from a block of billet EN AW 7075