Over Pressure Relief Valve (OPV) to provide a safety pressure relief for your pressure hose especially for your drysuit inflation system. On dedicated drysuit inflation systems there is no regulator second stage to provide relief should the high pressure seat fail. Without a way to relieve the pressure, the drysuit could begin inflating rapidly or the low pressure hose could rupture. The over-pressure relief valve provides the same fail-safe function as a normal regulator second stage. Screws into any available first stage low pressure port and provides protection from first stage failure.