This is the ideal starter kit. It has everything a beginner needs: hallow and flexible core, super-smooth medical-grade silicone, a user friendly insertable length and a large flange for easy grip. This kit comes with two sounds. Both are hollow and allow for piss or cum to pass though. One is thicker than the other, allowing for a progression. Or use one on yourself and one on a friend at the same time. Harness that powerful load and feel the unexplainable pleasure from internal stimulation when you finally shoot. PRODUCT DIMENSIONS Thin: Length: 5.1 cm. (2in.) Internal hole: 2.25mm. (.1 in.) Shaft: 4mm. (.16 in.) Ridge 6.25mm. (.25 in.) Flange: 15.35mm. (.6 in.) Thick: Length: 5.1 cm. (2 in.) Bump: 8mm. (.35 in.) Center: 6.35 mm. (.25 in.) Internal hole: 3.4mm. (.13 in.) Flange: 15.35mm. (.6 in.)