This 3-piece set of silicone caps fits the Womanizer Duo and Inside Out. When used regularly, we recommend that you replace your Womanizer\'s silicone cap every 6 months. When exposed to air, silicone can harden, which will make your soft cap feel less comfortable. . What is the difference in the sizes? The difference between sizes S and M is not just in the opening, but also the height, the M cap is a bit higher. Take good care of your Womanizer, clean your toy after use with a toy cleaner or a mild, antibacterial soap and lukewarm water. Dry the toy with a lint-free cloth and store it in a dust-free place.