10A PISTON of 1piece Composite (STD) 6.5" for PZ-8 Mud Pump Part No.: 324PZL350 Piston assembly is the expendable parts at the drilling pump hydraulic system, and it is one of the biggest wearing parts of drilling work. The piston core is made of 42CrMo. Lake Petro can supply F series,3NB series,9-P-100/13-P-130/12-P-160 series, PZ7/8/9 series of drilling pump piston assembly metric (inch) with various sizes. The piston rubber is also called the piston cup, its the expendable parts at the drilling pump hydraulic system, and it is one of the biggest wearing parts of drilling work. The piston rubber is made of rubber vulcanization. The material of ordinary piston rubber is NBR. But if you use the PU can enlarge the work temperature range.