Unleashed Performance Stage 1 Mod Kit for Nerf Alpha Trooper This kit includes metal trigger catch, 2x double strength trigger catch springs, reinforcement plate, and 5+ kg mainspring (2.5kg stock). When installed, the Alpha Trooper shoots 70fps muzzle velocity with up to 50ft range (parallel to ground) and up to 70ft range (30 degrees angled to ground). WARNING: Does NOT work for Elite Alpha Trooper. Mod at your own risk! Increasing the spring tension can break or damage stock internal components of your blaster. Blaster not included.