Made of aluminum alloy to make them more durable, stronger and lightweight. Spring of carabiners allow them to be quickly and securely attached to a wide range of fixing points. Not for climbing use. Suitable for outdoor hiking, fishing, camping, traveling. You could attach it to your sports bottle, camping gear, hanging lanterns and lights, backpacks, ropes of camping tents, or use as a key ring. Customized logo is available.