ERGO is a super smooth silicone buttplug designed for comfort. Its kidney bean shape and tapered neck are designed to keep ERGO snugly in place. It's made from high quality Pure Platinum Silicone so it's blubbery and flesh-like, perfect for comfortable insertion. Each ERGO buttplug is hand poured in our factory so no two plugs alike. It's available in 5 sizes ranging from beginner to advanced hole-stretcher.M : Length: 4.25”/ 10.795 cm Usable Length: 3.75”/ 9.525 cm Largest Usable Circumference: 6.25”/ 15.875 cm Smallest Usable Circumference: 3.75”/ 9.525 cm.