The faucet stem or cartridge controls how much hot and cold water you receive, and lets you change the water's temperature. The bonnet nut is used to hold the faucet’s stem or cartridge in place.
VMS stocks O.E.M. compression stems, ceramic disk stems, plastic stems, brass stems, Delta balls, ceramic cartridges, two handle stems, single lever stems, balancing spools and others from all of the major manufacturers including; American Standard, Bradley, Chicago, Delta, Elkay, Kohler, Moen, Symmons, Powers, Price Pfister, T&S Brass, Sloan, Zurn and others.