Precision parts made primarily of rubber or plastic materials, namely, customized sealing elements in the nature of ball seals, O-rings, V-rings, X-rings, four-lobed sealing rings, six-lobed sealing rings, bonded mechanical seals, lip seals, pipe seals, poppet seals, rod seals, valve seats, washers, gaskets, and pump diaphragms, bellows, bladders for accumulators, wipers and scrapers for reciprocating rods, being parts of machines