These penis-shaped sounds give you three options to play with. Work your way up from the small urethral insert to the large to experience unique sensations of pleasure. An increase in size occurs halfway down each shaft. They are textured with a bulbed head and veins, very subtly in the smallest and most prominently in the largest. Made of flexible silicone, these sounds are body-friendly and comfortable to use. Silicone. All 3 sounds are 8 inches in length. Small diameter increases from .20 to .23 inches. Medium diameter increases from .28 to.30 inches. Large diameter increases from .35 to .39 inches. From XR Brands.