AirsoftPro show the Snow Wolf M24 M150 Upgrade Set that they offer to those who buy the M24 airsoft sniper rifle from them... "Only at AirsoftPro you will get FOR FREE the AirsoftPro M24 UPGRADE SET: M150 spring, CNC piston and 7mm steel spring guide, which simply increases the muzzle velocity up to 500 FPS (150 m/s)!