This is the Zeagle Heavy Duty Nylon Tank Pouch fits 20 cu ft Pony Bottles Features: Made of Heavy Duty Nylon Fits 20 cu ft pony bottle (5.25 diameter) Two double ended snaps the pouch can be mounted in a variety of locations on your BC This heavy duty nylon pouch is made to fit the 20 cu ft pony bottle (5.25" diameter) included in Zeagle&';s 20 cu ft Pony Bottle System. With two double ended snaps the pouch can be mounted in a variety of locations on your BC. "