This is a key ring made by combining TPU (thermoplastic polyurethane) and stainless steel pipes. It can hold multiple keys stacked together. I bought it to hold my YubiKey security hardware, but the thickness of the pipe (4.2mm) that the keys pass through barely fit the size of the YubiKey's hole, so I couldn't use it and it's been sitting unused. It's well-made and excellent as a key holder. The photo shows an example of keys attached. The keys are not included in the sale.