A jet assembly has internals rotatably and releaseably fit to a jet body, such as that for a spa. The wire protective film andor barrier film is formed with a cobalt alloy film containing cobalt, at least one of chromium, molybdenum, tungsten, rhenium, thallium and phosphorus, and boron. A restrictor is provided for engaging the portion of the pressure source passing through the restrictor housing and is adjustable to variably alter fluid flow through the pressure source portion.