PT Coupling Company is a family owned business founded by RC Parrish in 1951. PT is a division of Parrish Enterprises Ltd. aka Parrish Manufacturing Group. Parrish has 340 employees. PT is a US manufacturer of cam and groove hose couplings. Couplings are made from aluminum, brass, stainless steel, ductile iron, polypropylene, nylon. PT Stainless Steel cam and groove couplings are produced in 2 foundries in the USA. Oklahoma Investment Castings in Blackwell, Oklahoma, acquired by Parrish Enterprises Ltd. in 1984, and Mississippi Precision Cast Parts in Columbus, MS, established in 1994 by Parrish Enterprises Ltd. Both investment casting foundries are ISO 9001 certified. Alloys poured are 316, 304, 17-4, Carbon Steel, Alloy 20, Hastelloy. Material certifications are provided on request.