The Cold Steel Pocket Shark is made from glass-reinforced plastic, Grivory, the same tough material used in Cold Steel's Nightshade Series. Built for impact with walls that are 4 times thicker than similar markers. In a self-defense emergency it can become an efficient Yawara stick for driving off an attacker. Plus, the screw-top cap will stay in place and won't pop off like a regular marker's cap would when you strike. 7/8" thick. 6 1/4" overall. Cold Steel, 91SPB