The Fido creates a unique anal experience unlike any other! The middle knot acts as a plug that releases an amazing pressure when inserted and pulled out. The ribbing on the upper shaft stimulates the inner anal muscle band, and when combined with the sensation of the knot, creates an amazing experience. Made of 100% Ultra-Premium Super Soft ?silicone, this is an advanced toy for people who know what they are doing and demand quality from products they put in their bodies. Top Tip Diameter: 1.8 inches. Ribbed Shaft Diameter: 1.6 inches. Middle Ball Diameter: 2.5 inches. Bottom Shaft Diameter: 1.3 inches. Base Diameter: 2.8 inches. Length: 8 inches.