Taking hands-on play one stage further, this feisty Knuckle Up accessory will delight and amaze you using its novelty, functionality, and it is indisputable awesome factor. The Knuckle Up accessory works with the whole choice of Vac-U-Lock attachments, using its one-size-fits-all knuckle rings sitting below a typical Vac-U-Lock plug. You won't believe how versatile this toy is! It is ideal for both masturbation and having fun with someone! What exactly are you awaiting? Experience endless enjoyable options most abundant in easy to use adult toy system on the planet. Features: suitable for any Vac-U-Lock Attachment. One-size-fits-all knuckle ring grip. Phthalate-free, body-safe material. Comfortable during use. Dimensions 5.8 inches lengthy by 4.5 inches wide by .8 inch deep. Vac-U-Lock Knuckle Up Black from Doc Manley Novelties The Truly Amazing American Toy Company