It's a strapless strap-on designed to give skin-on-skin contact without breaking the continuity of action to adjust straps and buckles. It works! A person uses their internal muscles to hold it in place with the bulb as the shaft protrudes at a natural angle. The Tantus Strapless™ Slim is easier to hold and control than the original; the Slim is 10% lighter than the original model making it lighter for the driver. Vibrator: Single Speed Removable Waterproof Bullet Vibe Uses 3 x LR44 Type Batteries. Dildo Diameter: 1.25" . Dildo Length: 5.5". Bulb Diameter: 1.5". Bulb Length: 2.5".