Catalina Pony Bottle Tank with Pro Valve

The Catalina Pony Bottle Tank with Pro Valve is a small aluminum scuba cylinder you carry as a second, independent air supply alongside your main tank. It comes in five capacities, 6, 13, 19, 30 and 40 cu ft, and the valve on it takes either a yoke or a DIN first stage.

Who this suits

Divers who want an exit that does not depend on a buddy being close. Catalina splits the range by use itself: 6, 13 and 19 cu ft for sport diving, 30 and 40 cu ft for deep, technical, cave and wreck diving. That split is the fastest way to find your size, because it maps capacity to how long you might have to stay down before you can surface.

It also suits anyone who has not settled the yoke-versus-DIN question. The Pro Valve accepts both, so a regulator bought two years from now does not strand the bottle.

Skip it if your diving is shallow, in open water, and always within a straight swim of the surface. A pony adds weight, drag and a second regulator to service, and on that profile a direct ascent is already the plan.

Five sizes, and what each one costs you to carry

Capacity is the decision. Everything else on this listing is the same across the range, so the only real question is how much gas you want strapped to you and what that gas weighs and measures.

The 6 cu ft bottle is 10.8 inches long and 2.6 lbs, small enough to clip on and forget about. The 40 is 24.85 inches and 15.9 lbs, which is a full cylinder you have to rig, sling and trim for, and it will change how you sit in the water.

Every size is negative when full, between 1.3 and 2.6 lbs. That is 1.3 to 2.6 lbs you can take off your weight belt when the bottle goes on, and the figure drifts toward neutral as you breathe the gas out of it.

The Pro Valve takes the regulator you already own

As it sits, the valve accepts a yoke (A-clamp) first stage. The DIN insert is removable, rated 200 bar (3000 psi), so going to a DIN regulator means taking the insert out rather than buying a second valve.

That is worth more than it sounds on a backup bottle. Rental and boat fills abroad are often yoke, home kit is often DIN, and one valve covering both means the pony travels with you instead of sitting in a cupboard between trips.

The valve also carries a multi-ported burst disc plug, the pressure-relief fitting that lets a cylinder vent in a controlled way rather than fail. Catalina describes the mechanism as heavy duty with smooth operation.

Aluminum, and where it earns its keep

The cylinder is aluminum. Catalina's own corrosion note is the practical part: aluminum oxidizes into a thin protective coating instead of flaking away the way rust does on steel. A pony bottle typically gets less attention than a main tank between dives, so a metal that partly protects itself is the right one for the job.

The cylinders carry DOT-3AL and TC-3ALM certification, the US Department of Transportation and Transport Canada specifications for aluminum cylinders. If you dive outside North America, check that your local fill station accepts those before you buy.

Nitrox ready is listed as yes. The listing does not state an oxygen percentage, so confirm the mix limit with your fill station rather than assuming a number.

Which version this page covers, and how it arrives

This page covers the Pro Valve configuration across all five capacities. The size you choose changes the height, the weight and the buoyancy in the table above, and nothing else in the specification.

Plan for one thing before your first dive with it. Catalina ships these with the valves removed, and the cylinder needs re-inspection before it can be filled. So it is not a bottle you unbox on Friday and dive on Saturday.

For mounting, the listing gives three options: on your side, on the front of your body, or fixed to the main tank.

The bottom line

A plain aluminum redundant air source with a valve that fits whatever first stage you own, in a size range that stretches from a controlled ascent to a real overhead reserve. Take Catalina's own split as your starting point and buy for the diving you actually do, not the diving you might do in three years.

Two things to budget for beyond the cylinder. A pony is only a backup once it has its own regulator on it, and this one needs an inspection and a fill before it does any work at all. Get both sorted and it is one of the least complicated pieces of safety equipment you can add to a rig.

Specifications