... against the housing.6) Rotary applications need only one hydraulic seal (single acting) because it can seal in the one axial direction ... working procedures. Application of Seal in Various Industries General mechanical cylinder appropriative seal:USH, UPH, USI, UPI, ODI, IDI, OSI, ... , SPNRI, WR, BRT, RYT, DB, TAY, VB, TC Pneumatic Cylinder appropriative seal:PGY, PNY, GLY, PSD, PDU, PPY, PRY Automotive ...