J-Style Packing is the most common plunger pump packing. It is composed of nitrile butadiene rubber (NBR) with synthetic fabric around rigid phenolic core, medium hard, black. 838 plunger pump packing is an industry staple for fluid seal in reciprocating plunger pumps.

The popular general service 838 plunger packing is composed of nitrile rubber and synthetic fabric is recommended for service in fresh water, saltwater, propane, butane, gasoline, light or heavy oils, mild chemicals and acids, and most hydraulic fluids.