High Quality Content by WIKIPEDIA articles! Captains of Crush Grippers (commonly nicknamed CoC) are a brand of torsion-spring grippers (a torsion spring fitted with two handles) designed, manufactured and sold by IronMind Enterprises, Inc., based in Nevada City, California. They are the official grippers of the Arnold Sports Festival, the GNC Grip Gauntlet, United States Arm Wrestling and the World’s Strongest Man contest.