The Macho Vibrating Cock Sling gives harder, thicker erections, and the ultimate clit teaser stimulation. Super stretchy, this cock sling is waterproof, push bu tton controlled, and phthalates free. Requires 3 LR44 batteries, included. Cock sling is SEBS and Bullet is ABS. RoHS compliant. Bullet is 2.5 in.