3 out of 4 of these worked fine. The fourth doesn't move at all when inserted ...
3 out of 4 of these worked fine.  The fourth doesn't move at all when inserted into the toothbrush and turned on. Strangely enough, I may buy them again as they are so much cheaper than the alternatives.  If it wasn't for the useless 4th brush I'd have given them 5 stars.
Rating: 3 stars