This is the XS Scuba Tank Holder Silicone Band and Stainless Steel Hook Features: Easy to use -- just stretch and latch Corrosion resistant stainless steel buckle User-replaceable surgical-grade silicone tubing Corrosion-proof, durable, impact-resistant plastic base Interlocking base so you can connect an infinite number of tanks Mount tanks in either direction with the reversible design Includes 6 screws to mount the tank holder directly to any hard surface Combine with the Aluminum Tank Rail for a secure, convenient, Removable Storage System Secure tanks with adjustable-length bands Ideal for holding 7.25" / 184mm diameter scuba tanks Also capable of holding 6.9" / 175mm tanks and 8.0" / 203mm tanks Use the extender kit to secure a tank with BCD attached The Consists of a rugged, double slotted base with a removable, silicone band and stainless steel hook. The holder is designed to secure 7.25 in (184 mm) diameter scuba tanks. It can also fit 6.9 in (175 mm) and 8.0 in (203 mm) tanks, though the fit will not be as optimal.