Security to hit the wall of natural fracture, does not rebound, safer than steel ball; Easy to hit the target will leave a mark, more convenient, more clearly. High precision,seamless,roundness,polish Perfect spheres and no air pockets ISO 3290-2001 G1/GO,CE,CTS certificate have passed,highest industry standard Use for spring pistols,spring rifles,gas powered guns,AEG,ASG. Designed for tight high perfoermance barrels