This regulator hose has a NON-STANDARD 1/2-inch male fitting on one end for the oversized low-pressure (aka intermediate-pressure) port found on a few uncommon first stages, along with a standard 9/16-inch female fitting on the other end for a second stage.

In the 90's some regulator manufacturers (notably Apeks, Aqualung, and Mares) started offering some versions of their first stages with an oversized 1/2" low-pressure port. The oversized port has an optimized gas flow path and should be used to supply the primary second stage. (Mares calls it a DFC port.) While the oversized and optimized port does slightly improve machine test results in simulations, most divers found it does nothing significant for actual in-water breathing performance and also inconveniently requires a non-standard regulator hose.

Today, most manufacturers have deprecated their oversized port on first stages for the recreational market, although it continues to be available on versions for the military market. (Just to be clear, Dive Gear Express does not sell any regulators with non-standard sized ports.) If you are now seeking a replacement 1/2" regulator hose for a regulator you purchased elsewhere, instead your best strategy might be to just plug the oversized port and use one of the other standard size low-pressure ports; we stock 1/2-20 UNF port plugs. If you really want to use that oversized port, we have a 1/2-20 UNF male to 3/8-24 UNF female port adapter that will allow you to use reasonably-priced standard low-pressure regulator hoses.

Some regulator manufacturers still offer a few hoses with a 1/2-20 UNF male fitting that will work with the oversized 1/2" port on any brand first stage, unfortunately almost no dive shop stocks them due low demand and their also oversized price. Regardless, you should buy an adapter for your save-a-dive kit because if you have an unexpected need for a replacement 1/2" fitting hose you have a better chance of finding a pot-of-gold at the end of that rainbow. Really, it might be more prudent to buy just the adapter and forget about the special hose.

The generic DGX adapter and plug have a compatibility problem with the Apeks 5th Port Upgrade for DST first stages. The 5th port turret retaining bolt has a larger diameter center than the standard bolt and some non-Apeks brand plugs and adapters (including ours) have enough threads that they will bottom out against the internal side of the larger bolt. This will either not seal the O-ring or lock the swivel in place if over-torqued enough to force a seal. The resolution is to use the more expensive but shorter Omniswivel brand versions that have fewer threads. As far as we are aware, this issue only applies to the Apeks 5th Port Upgrade for DST first stages.

Miflex2™ manufactures regulator hoses with a 1/2"-20 UNF fitting in a few lengths for the European market. Unfortunately, the US distributor for Miflex2 does not import the 1/2" versions due to lack of demand and so the Miflex2 branded hoses with 1/2" fittings are not available to us directly.