The first stages of modern SCUBA regulators have 3/8-inch 'Low-Pressure Ports'. The second stages of modern SCUBA regulators have 9/16-inch fittings to connect the regulator hose to the second stage body. These fittings are very standardized and your regulator almost certainly is compatible with these same fittings on our LP regulator hoses. However, there are a few rare exceptions: A few brands of first stages include one special low-pressure port that is 1/2-inch, notably some older Apeks, Dacor, and Mares models. For these rare exceptions we stock first stage port adapters.

Older Poseidon brand second stages are also a special case. Historically, Poseidon incorporated the OPV for their upstream second stages in a unique fitting on the end of their non-standard low-pressure second stage hose. In 2008 Poseidon updated their designs (the Mk3 designation) to no longer require a Poseidon-specific low-pressure regulator hose, but we do have a solution for using standard regulator hoses with vintage Xstream and Jetstream second stages. Cyklon regulators have unique hose compatibility issues and often require special hose fittings or adapters.

A few brands of second stages used with full face masks have a unique fitting, notably the Interspiro AGA models. In fact the fitting is generally referred to as the 'AGA' fitting. For the rare AGA and Poseidon exceptions we also stock LP regulator hose to second stage swivels that adapt their unique second stage fittings to standard hoses.