Bamboo is the most popular, but they can be made from bamboo, organic cotton and hemp - anything you can put inside to help absorbency! Our favourite is the little weeds pad, super versatile and absorbent but very quick drying. Hemp is super absorbent (probably the most absorbent on the market), however, the trade-off for the super absorbent pad, is the drying time. Hemp is ideal for heavy wetting toddlers!