REVHAMMER shaft-strapped shaker is a COCKRING plus shaft-ring that puts the vibe shaftwise, lengthwise up on top, its got a rubbery front nub that seeks to aim at any hole you wanna slide into - every thrust missiles the buzz-vibe up against the gape-lips - or even the BJ's pucker - REVHAMMER sends vibe into the both your shaft and the lucky shaftee. Good stuff! Every thrust moves the hummy-buzz deeper, closer to its target - the boys at hunkyjunk wanted a piece of vibe-gear you feel penetrating and feel getting penetrated. REVHAMMER straps on with a rubbery cockring in back, the vibe lays on top of your penis and the front ring stretches around your shaft about 1-1.5- from the base. The rings secure the reverb-vibe for lots of hard play. We like JO with this thing humming at the base of our penis and having sex with it - it's excellent couples gear. Cool feature: there are shaft-top ribs under the rubbery vibe that holds lube to rub you right. Like everything hunkyjunk - REVHAMMER fits a need and more, it feels right, fits right and lasts, the rubbery-firm Plus+SILICONE mix is super-soft stuff with a slick smooth velvet finish that's super-rubbery tough. HOW TO: a bit of light lube on your penis, slide your penis through front bigger ring, your shaft through the smaller ring. Click the waterproof, silicone sealed buzz-vibe on and hammer away. VIBE UNIT: 3 button batteries give 5-7 hours of vibration. Battery size: LR44, comes with three.