These Seamless projectiles are extremely dense injection -molded Nylon rounds designed for maxim impact and distance. Please use riot balls responsibly. 100 X 0.68 Cal. Balls - Seamless Self Defense Less Lethal Paintballs - Riot Balls, Seamless Black PVC/Nylon, Personal and Military self protection rounds 3.5 Grams The Seamless .68 Cal Nylon Riot Training Balls can be used thousands of times. They just need to be swept up, rinsed, dried and put back in action! Seamless Self Defense Paintball Ammo Alternative - about 17mm or .68 - They work in all .68 cal. paintball guns, They are reusable, do not deform and long lasting The .68 Cal Nylon Riot Training Balls are the latest non-lethal training munitions available today. These work great and are intended for practice target shooting and possible home defense against intruders or animal attacks.