This is the Innovative Scuba EZ-On Pony Bottle Holder/Mount Cam Style Bands Features: Anodized Aluminum construction Cam style mechanism holds pony bottle securely in place Stainless steel cam buckle, protective rubber feet Designed for 4.4 inch diameter pony bottles, 8, 13, 19 cu ft Designed for 6.9 - 8 inch diameter primary cylinder Easily attach your Pony bottle with this easy-to install holder from Innovative Scuba Concepts.