Bought the wrong ones... hoping to find someone that can use them. These will save you $25 if they fit yours.
Full disclosure: I did try to put one on my handle, but quickly realized I messed up. The head cover is still on and the other is still in the interior plastic bag.
74th & Marshall area.
Waterpik Sonic-fusion brush heads (Newmarket NN)
This offer has been gifted to someone and is no longer available.