CNC-machined aluminum top surprise limit for shock human anatomy created from premium lightweight Swiss 7075 T6 aluminum. Black color. Set of 2. The upper aluminum cap features a little vent opening that produces shock construction extremely predictable and easy, since excess surprise oil will escape through this vent opening making sure just the proper level of the oil is inside the shock construction. Machined interior ridges confirm appropriate placement and sealing of the super-soft silicone membrane.