Primary Fluid Systems Inc. has introduced a new line of diaphragm style back pressure valves and pressure relief valves named TOP VALVE. These new valves feature a completely adjustable pressure range of 15-150 PSIG and a built-in air release to reduce priming difficulties with metering pumps. They are available in seven sizes, ¼ in through 2 in NPT and eight materials of wetted construction. The seat design extends the normal life expectancy of the diaphragm and the valves have color coded handles to indicate size at a glance. High temperature valves are available as are high pressure all metallic valves. The line is available in PVC, CPVC, PVDF, polypropylene, Teflon, stainless steel, Alloy 20 and Hastelloy C.