The KWA LM4 series is renowned for their hyper realistic function and amazing performance. However, some users find that velocity in the LM4 is lacking. KWA Performance Industries has developed this high power bolt assembly to drop into all LM4-based platforms including the LM4 Rifle, LM4C, and the PTS Mega Arms MKM. This effectively increases the FPS to 450 to 470 FPS with .20g BBs. The bolt currier is made entirely out of steel with steel allen screws and bolt carrier key. The bolt itself is made out of reinforced nylon-fiber polymer to keep the weight down for efficient gas consumption. The assembly is complete and installed in a matter of seconds. Made in Taiwan by KWA.