These angelcare refill cassettes are suitable for use with the angelcare nappy disposal system only the refill cassette is an airtight barrier bag to retain bad odours from your little ones nappiesfeatures benefits optimal convenience and keeps nasty smells at bay only one type of refill cassette suitable from birth unique airtight barrier bag to retain bad odours one refill cassette lasts approx 28 days 128 nappies size 2 monthly costs are comparable to the use of premium