Nuby Sonic Toothbrush uses high-frequency vibration to thoroughly clean children’s teeth. The vibrating bristles quietly but effectively fight plaque to keep your little one’s smile healthy and bright..Designed with a smaller brush head to comfortably fit in little mouths. The toothbrush heads feature soft bristles that thoroughly clean teeth while being gentle on gums..Each toothbrush head is engineered for optimal use with the Nuby Sonic Toothbrush. Designed specially to work with the toothbrush’s high-frequency vibration—up to 38,000 strokes per minute..Dentists recommend changing your toothbrush head every three to four months. It is important to regularly change your toothbrush head as bacteria can collect in the bristles, or bristles may become frayed and less effective..Toothbrush replacement heads are compatible with Nuby Sonic Toothbrush. Comes with 4 replacement heads, enough for 12 months when following dentist-recommended standards.