I have several inexpensive watches that occasionally need batteries. It is more convenient to change them myself than finding a jeweler who will charge more for the job than the watch is worth. Many watches have screw backs which require a special spanner wrench (which I also bought on Amazon) but this tool is for those hard to remove snap on backs. Watch backs used to come with a small area raised so it was easy to pry them off with a knife or small screwdriver. Lately they seem to be missing this feature and a knife edge has to be pushed under the edge of the back. This is not only difficult but is dangerous and can mar the case. I have used a small round edged knife made for this purpose but it is also hard to use. I received this tool a couple of days ago and easily opened a watch case already. Unfortunately the edges of the tips were too thick but I easily filed them down to a narrow almost knife like thickness. That's the only reason I didn't give it a 5.