The best-performing filter for bacterial reduction*: With an ultra-filtration antibacterial membrane. Most standard water filters don’t include an antibacterial filtration membrane, so won't remove the same amount of bacteria One filter lasts up to three months**: Depending on the amount and size of bottles you use. The performance of other filters deteriorates over time*, ours work like new for up to 3 months**​ Compatible with Tommee Tippee bottle prep machines: Our filters are specially designed for use with all Tommee Tippee Perfect Prep machines ​ Know when a new filter is needed: Your Perfect Prep machine or app will let you know when it's time to fit a fresh filter​ No need to use bottled, filtered or pre-boiled water: Tap water passes through an antibacterial filter to make sure it's clean, safe and ready to make a fresh formula feed for your baby