Mommy's brushing?kids under 7 years old Minus ion Toothbrush Use battery. Good-for-health ions will directly reach gums and teeth then remove plaque effectively. Excellent ion action will also help maintain healthy gums. Features ●Economical toothbrush with replaceable brush head. ●3V battery (battery life: more than 1 year) 　The flashing checker allows users to check remaining battery. ・3 columns of bristles ・Super small head ・For mommy's brushing?kids under 7 years old ・Hardness：Regular