The Retro Arms Billet Version 2 Gearbox Shell is available in the U.S.A. under the EMG brand. You can order this from the Evike.com online store... "Unlike 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.

Version 2 Retro Arms gearboxes feature a quick-change ball-bearing spring guide mechanism, allowing spring swaps in a matter of minutes without complete gearbox disassembly.

Features:

• Precision machined from a block of billet EN AW 7075 T651 aluminum
• Quick change spring guide system
• Durable anodized finish
• Reinforcement in key stress points to counter rapid wear from high performance parts
• Pre-radiused cylinder windows - helps evenly distribute impact force
• Deeper wire channels along base of gearbox
• EMG Logo engraved on side of gearbox"