It is waterproof, highly elastic and explosion-proof Great Affordability - Made of high quality material, not easy to blow up within a safe diameter. Smooth surface, soft to the touch. Non-toxic and odorless; Easy to Use - Unscrew the knob counterclockwise to deflate the air. Turn clockwise and tighten while inflating; Adjust size - Adjust the size at any time, you can try different emotions that transform between deflating and inflating. Suitable for all types of players; Suggestions - Suggest some experience with lubricants. When you start inflating it is normal to find yourself deformed due to the flow of air.