This attaches to rail of a cot and holds a “D” cylinder. It attaches with a 2” hook and loop sewn to 2” webbing. There is a hook and loop tab sewn to the top where you can coil your oxygen or mask tubing and store it when not in use. A small side pocket holds extra masks. It is available in either orange or green. It weighs 8 oz. and the overall dimensions are 15 3/4”L x 4 1/2” diameter.