It's A Pack of 50 Rounds .68 Cal Hard Aluminum Balls. Crafted From Top Class Aerial Aluminum Alloy. Fits Perfectly for Umarex T4E HDR68/ HDS68/HDX68/ HDB68 and Byrna Series(SD/LE/EP) Launchers. Can Be Recovered And Reused Over and Over. 7.3 Grams Each Ball. Much Heavier And More Powerful Than Rubber Balls And Plastic Kinetic Projectiles. Silver Color, Smooth Finish, Seamless, Mirror Polishing For Super Precise And Significantly Round. Fly Far and Fast ,Hit Accurate and Hard.