A high specification hole seal made up of 4 separate fittings when the SPW hole is used as a main seal. This design optimizes the mounting groove size of the piston. The special PTFE resin material can avoid the crawling problem of the sealing ring under the U-ring structure. The needle's compression resistance to SPS was insufficient, and special nylon rings were added on both sides of the resin to increase durability. The HNBR rubber at the bottom is the force agent, providing the support required for the sealing system.