Silicone oil for dampering. Module 0.8, Number Of teeth: 11, Pitch circle 8.8, Pressure Angle 20, Resistance ... gf.cm Silicone oil for dampering.Module 0.8, Number Of teeth: 11, Pitch circle 8.8, Pressure Angle 20, Resistance ... : make the opening and closing smoothly, provide excellent usage feeling to user. car audio damper