The Smart Bottoms Lil' Trainer is a great helper for any potty toddler. The trainer is unique for the organic cotton both inside and outside, the insert that can be fixed with two snaps and the PUL, which is found in the central "wet area". This trainer is designed to facilitate training for normal amounts of pee absorbed by its 6 layers of cotton and is not waterproof throughout. the additional insert is essential for a quick change, or it can be removed completely when accidents are minimal and to make it even slimmer. material: Inside: 100% cotton (organic) Outside: elastic jersey 50% cotton (organic), 50% polyester Care instructions Before first use, the trainer should be washed 6-8 times to get the right absorbency. Test the absorbency by putting water on the dry diaper; the water should be absorbed immediately. If not, it's not ready yet. Do not use bleach or fabric softener. Available in sizes S, M and L