Your Perfect Prep machine is designed for use with water straight from the tap, so there is no need to pre-boil the water using a kettle or use bottled water. The Tommee Tippee Perfect Prep filters feature a unique filtration membrane which removes bacteria and other contaminants that can be found in water. This ensures that your water is clean and safe to make a bottle feed. The Tommee Tippee plain white filter and blue/white filters are compatible with both Perfect Prep Machines.