The perfect introduction to unisex anal play, Peridise continues the Aneros tradition of intelligent design. You have never experienced an anal toy like this before because there is never been anything like it. By utilizing the body's natural responses after insertion, Peridise begins to quiver on its own, generating an orgasmic response that can stand-alone or enhance a traditional orgasm. The thoughtful design of the Peridise allows for easy introduction, comfortable use, and a freedom of movement for an experience like no other. As your skill and strength advances, you should start with the larger model and move down to the smaller. You will find that the smaller the device, the more exquisite the pleasure.Head Diameters: .87" inches and .63" Inches Total Length: 4 inches.