This spring has a power output of over 8 kilogrammes (4.5kg stock) and will bring the muzzle velocity of your blaster up to 80+ feet per second while maintaining the ease of use. WARNING - Some of our products may contain plastic wrapping and small metal parts that could present a choking hazard in young children. Product not intended for children under 8 years of age. Increasing the firing velocity of your blaster can result in injuries if not used with the proper respect. Have fun, but remember to use your blaster responsibly. Neither Orange Mod Works nor Hasbro, Inc. can be held responsible for injuries incurred due to careless blaster use. Orange Mod Works strongly suggests the use of safety glasses during use of your modified blaster.