Made of premium. non-porous silicone. these urethral sounds are easy to sterilize and body safe for an all new sounding experience. These flexible rods bend with the body. sliding down the shaft for that unique sensation. Each sound is double-sided. with a different sized girth on each end. The graduated sizes allow you to work your way up until you can accommodate the largest rod. Each sound is 8 in. long. The smallest has a diameter of 0.19 in. on one side and 0.23 in. on the other. The medium is 0.27 in. and 0.32 in. wide. The large is 0.34 in. and 0.38 in. wide.