This is an item used during diving to attach things like underwater slates, cameras, and lights to your BCD, allowing you to extend them when needed. It has a quick-release buckle and a one-touch snap-in function, making it very convenient. You could say it's insurance against losing things underwater. It's surprisingly easy to drop things while diving. Please don't lose anything as important as your life. Attach your precious soul to this "biniyo~n" (stretchy thing) and be careful not to have an out-of-body experience. Attaching your soul after an out-of-body experience underwater isn't covered in the Open Water course, you know. I forgot the official product name, so I'm calling it "biniyo~n." Diving Scuba Diving Underwater Gadgets Snorkeling Free Diving Skin Diving