Each cassette has an advanced multi-layer anti-bacterial film which locks away germs and odours. The film keeps on killing germs even while the nappy is disposed of in the tub for maximum hygiene protection. The cassette gives unbeatable odour protection. Twist-lock technology individually seals each nappy locking away germs and odour. Just drop the cassette into the top of the Sangenic Nappy Disposal Unit (sold separately) and it's ready for use in seconds. Each cassette lasts up to approximately one month (based on average use using Size 3 nappies/5-9kg using three nappies per day).