A DIN or a Yoke Regulator? It’s Time To Know The Difference

There was a time when every regulator was fitted to a tank valve by means of a yoke fitting (officially known as an International A-Clamp). The tank valve has an O-ring, and most divers have been affected by annoying leaks and blown O-rings because these can wear and fray. A DIN connection solves this problem, and that's why regulators are now available in both DIN and yoke configuration.

A DIN-fitting regulator has a permanently captive O-ring and screws securely into the tank valve. Technical divers prefer them because the O-rings rarely wear or blow, and the simpler shape of the DIN regulator, devoid of the yoke, means there's less likelihood of entanglement with lines and gear.

Another plus: DIN-fitting regulators with the required number of extra screw-threads are rated for use on suitable tanks with higher pressures (up to 4350 psi), so you can make longer dives. (Never use a yoke regulator on one of these high-pressure tanks, even if you can find an adapter to fit it, because the pressure is too high to be considered safe.)

With the rising DIN regulator popularity driven by the technical diving community, you may think your American-bought yoke regulator will not fit tanks provided overseas. Don't worry. Most standard-pressure DIN tank valves worldwide are convertible and accept a yoke regulator by means of a screw-in slug. Some of these adapters offered by dive operators in distant countries look a little tired, so prudent divers carry their own adaptor -- they cost only a few dollars at your local dive shop and take up no space in your carry-on.

If you decide to buy a new DIN-fitting regulator, you may have problems in the U.S. or Caribbean because most tanks are A-clamp-fitting only and not convertible. So you'll need to add a yoke adapter, also available from your dive shop.

Both DIN and yoke-fitting regulators are usually made from chromed brass. If you use a yoke adapter made of lightweight aluminum, don't leave it on your DIN regulator if you're storing it for long periods. In the presence of seawater, electrolysis between different metals can make the yoke adapter impossible to remove later.

A cautionary note: In many European Union countries (but not the U.K.), tanks designated for nitrox have a different thread (M26) than those for air (M25). Check with your dive operator abroad to make sure they have tanks that are used for both air and nitrox, in which case they'll be suitable to use with either DIN or yoke regulators. M26 DIN-fitting regulators are normally color-coded green, are compatible with 100 percent oxygen, and are usually the exclusive province of technical divers.

-- John Bantin