Enlarge and stimulate your nipples using a vacuum pump (sold separately). The pair of ABS plastic cylinders is crafted from industrial grade clear acrylic. Uses an airlock release system. Can be used to create great stimulation or punishment with higher pressure levels. Small size is 3 inches long not including tip, 1.125 inches outer opening diameter, and 0.75 inch inner opening diameter. Please note cylinders only, pump not included. Sold separately.