Vibrates and expands when pumped. Easy to insert with its tapered/smooth texture and easy to remove with wide rim at the bottom. The pressure bulb and vibrator control are long so the device can be inserted and you can get dressed and walk around with it. Easily cleaned. (Takes 2AA batteries) - 4.75 total" top to bottom, 1.5" diameter and 4.75" around at its thickest point. When inflated it can expand to about 8 inches around.