Polypropylene aka plastic or poly camlock fittings are available from 3/4" to 4" on the basic standard cam & groove couplers. Our Made in the USA polypropylene camlocks (cam and groove) couplings are made from a glass filled composite making our fittings stronger and tougher. Polypropylene and nylon fittings the first choice among several industries for dry bulk, food applications, liquid transfer and transport.