New! This transparent anal plug is completely open on the inside. after you have inserted the anal plug into the anus, you can use the tunnel to add additional lubricant for wet play. the possibilities are endless.sizes:medium - insertion length 8.9 cm - circumference 17.5 cm (inner diameter of 15 mm draining to 18 mm)large - insertion length 11.4 cm - circumference 22.3 cm (inner diameter of 33mm draining to 22mm)extra large - insertion length 12.7 cm - circumference 25.4 cm (inner diameter of 40 mm draining to 28 mm)material:a blend of silicone and tpr, which ensures good stretch, comfort and durability. feels sturdy.the tunnel anal plug is suitable for all lubricants, plasticizer-free and contains no latex. can be cleaned with mild soap and warm water. we recommend cleaning before and after use.use sufficient lubricant on both the outside and inside.