Made of hard aluminum alloy, it is incomparably hard. Polished with D-type aluminum alloy, it is waterproof, wear-resistant, high-strength and durable. It can be hung in backpacks, key rings, kettles and everything else you need, and can be used for tents, ropes and other connections, fashionable and practical, comparable to non-inferior quality. Special instructions are not recommended for use in mountaineering, rock climbing, ice climbing and high-altitude games for safety reasons. Length: 81mm, Diameter: 7mm, Width: 41mm, Weight: 20 grams, Material: Aluminum alloy.