They're made with a hard plastic base

Most vibrators are made from a soft, smooth material known as silicone. A few types of vibrators are made out of latex, which is also hypoallergenic and non-porous.Silicone is much more expensive than latex, but it's worth the investment because it's safer and feels better on your skin. If you're using a rose vibrator, it's typically made from silicone or latex and has a soft, pliable feel. Typically, they're made with a hard plastic base which is the part that holds the batteries in place. The vibrator itself is usually made of silicone or latex—both materials can be used with water-based lubricants. Silicone is more expensive than latex, but if buying one isn't in your budget right now, you can use any other type of non-porous toy safely with any lube (like silicone).