Packing is one of the most common and simplest seals for positive displacement pumps. Packing typically consists of braided or formed rings that are compressed in the stuffing box of a pump. As the packing is tightened, it squeezes up against the shaft and the stuffing box wall to create the seal.

When the pump is operating, process liquid cools and lubricates the packing. The pump must leak or "weep" slightly to ensure proper lubrication.