Silicone nipple suckers have a wide opening that allows for the suction of a large area. The unique easy push design creates a powerful vacuum that clings tightly to your flesh. As blood flow to the nipples increases, they will become more sensitive. Not compatible with silicone lubricants. Measures 2.5 inches overall diameter, 1.75 inches high. Opening diameter is 1.6 inches with an insertable depth of 0.75 inch.