This compact test apparatus allows several very important regulator functions to be examined with highly accurate instrumentation. This tester can check the intermediate pressure, lockup, staging integrity, and initial inhalation / exhalation of any dive regulator without any major disassembly. First stage operation can be examined by merely attaching the BC hose to the tester. To connect the various types of BC hoses in existence to the coupler, three special adapters are provided. Instrumentation features a 4.0" diameter breathing effort gauge (2" scale) and an analog gauge (300 psi) for intermediate pressure protected by an overpressure valve. Housed in a robust, aluminum, desktop style case.