CNC-machined aluminum top surprise limit for surprise human body created from premium lightweight Swiss 7075 T6 aluminum. Black color. Pair of 2. the top of aluminum limit features somewhat vent opening that creates shock construction incredibly predictable and simple, since extra shock oil will escape through this vent opening ensuring just the proper degree of the oil is inside the surprise construction. Machined interior ridges confirm appropriate positioning and sealing of super-soft silicone membrane.