Material:food grade silicone gel  Function:10-frequency vibrations  Property:Waterproof and silent  Battery:1 pc of AA batteries(not included)  Size:            Option a: length-8.1inch  , small one inserting diameter is 0.21 inch and large one inserting diameter is 0.29 inch            Option b: Length-17.8inch, Inserting diameter is 0.21 inch