JoFan they are a small bendy cup that you insert into your vagina (as easy to get used to as using a tampon). It collects the blood, you remove the mooncup every few hours, tip the contents in the loo, rinse it, and reinsert. It sounds as if it could be revolting, but somehow, it really isn't. People feel evangelical about them as they are so enjoyable to use, save money, clean and eco-friendly, and can reduce period pain and length of menstruation because they don't leach blood and moisture out of you!