Worked OK in Waterpik WP-900
Worked OK as a replacement battery in a Waterpik WP-900 sonic toothbrush.  Original battery lasted about 2.6 years.  You need a soldering iron and several clamps/holders (or a second person) for the replacement process.  Checkout the web for replacement videos.  Rating of 4 stars for now, 5 stars if the batteries last a couple years.
Rating: 4 stars