Regulators - SPGs - HosesClick Me!
Regulators, SPG's, Hoses, Adapters and Accessories
Piston vs Diaphragm... Does it really matter?
At the risk of annoying those who do have a preference for a specific type of first stage design, the simple answer for most divers is NO the design type of the first stage does not matter. Piston type first stages are simpler designs with a lower parts count and thus generally considered to be more reliable. Because environmental sealing is easier and more effective for diaphragm type regulators, they are generally considered better suited to cold water or dirty water diving. Keep in mind that much of the opinion often heard expressed is a result of theoretical considerations or manufacturer marketing, not based on the actual characteristics of modern scuba regulators. Today, both piston and diaphragm first stages are very reliable and both can flow more gas than the diver can breathe.