The Tommee Tippee Sangenic Refill Cassette Fits All 6 Pack has an advanced multi-layer cassette and anti-bacterial film which locks away germs and odours. The film uses 60% less plastic than premium nappy sacks and keeps on killing germs even while the nappy is disposed of in the tub for maximum hygiene protection. Proven protection from germs and odours that kills 99% of germs on contact. With a twist-lock technology that individually seals each nappy means a 100x more effective odour prevention than nappy sacks. Just drop the cassette into the top of the tub and it is ready for use in seconds. Each cassette lasts about 1 month (based on average usage of sized 3 nappies).?