Primary Fluid Systems Inc has introduced a new line of diaphragm style back pressure valves and pressure relief valves. The features of the new Top Valve line include a completely adjustable pressure range of 15-150 psig and a built-in air release to reduce priming difficulties with metering pumps. The seat design of the back pressure valves and pressure relief valves extends the normal life expectancy of the diaphragm, and the valves are available in seven sizes: ¼ in through 2 in NPT. They are available in PVC, CPVC, PVDF, polypropylene, Teflon, stainless steel, Alloy 20 and Hastelloy C and have color coded handles which indicate size at a glance. The standard diaphragm is Teflon laminated and EPDM backed with a 3 year warranty.