Industrial Specialties Mfg.s new miniature plastic relief valves feature a unique, patented mechanism consisting of nylon bodies with 316 stainless steel springs and a silicone ball enclosed in polycarbonate housings. Thread sizes include 10/32, 1/4-28 and 1/8 male and 1-32 female. Colored muffler caps indicate pre-set pressure relief spring specifications from two to 14 psi. http://www.industrialspec.comsales@industrialspec.com