Extra Hard Type D Aluminum Mountaineering Buckle Knapsack Bottle Buckle Hook Hang Climbing Carabiner Keychain Outdoor (Green, 1 piece) Made of Hard Aluminums, it's very hard! Excellent material: Made of hard aluminum alloy material, it's very hard! Using D-Type aluminium Alloy, High Durable. Can hang kettle bag, key ring, kettle and all the necessary place , And can be used as a connection for the camps and ropes . IMPORTANT : Not recommended for mountain climbing, and high-altitude games!