The UV sterilizer effectively disinfects the brush heads, killing up to 99.9% of bacteria and helping you keep your toothbrush clean. After use, rinse the sonic toothbrush head under running water to get rid of toothpaste residue. Then place it in the UV sterilizer. The sterilisation process starts automatically when the door is closed and switches off automatically when finished. With the UV sterilizer built into the 3-head capacity station, the TrueLife SonicBrush UV and TrueLife SonicBrush K150 UV have a 3 head capacity. A separate 1-head UV sterilizer is included with the TrueLife SonicBrush GL UV. You can also purchase a separate TrueLife SnicBrush UV Sterilizer to accompany your toothbrush.