It may be my manual dexterity but I could not make this work. I could not get the back off of the watch. I took the watch to the jeweler and it took him 5 seconds, 10 tops to remove the back with a different tool. The quality of the tool seemed fine, but I could not get it to work. In fairness to the vendor, when I returned it, within 24 hours they notified Amazon and I got a credit from Amazon for the cost of $12.95. I was out the $4.80 return postage but they took it back without a quibble. Btw the jeweler charged $8.50 for changing the battery and that included the battery. It is obvious you can save money replacing the battery yourself but this didn't work for me.
If reviewing a product, it may have been received free of charge. That will NEVER have a bearing on my recommendations.