Control Devices CR Series Brass Pressure Relief Valve, 0-100 psi Adjustable Pressure Range, 1/4" Male NPT Relief pressure adjustable from 0 to 100 psi 1/4" male NPT threaded inlet connection Brass construction and stainless steel spring for corrosion resistance Silicon O-ring provides leak-proof seal to within 10 percent of set pressure Micrometer-style nylon knob for pressure relief adjustment