The Cross Action bristles is designed to reach between teeth and cover more surface for a superior clean in comparison to a regular manual toothbrush. The round head is designed for a tooth-by-tooth clean. The refill heads are compatible with all Oral-B rechargeable handles.Features and Benefits:- Features perfectly angled bristles to get deep in between teeth and remove plaque- Round head designed for tooth-by-tooth clean- Compatible with all Oral-B rechargeable handles- Does not fit Oral-B Cross Action Power (battery type) and Oral-B Sonic toothbrushes