These tools worked better than most I have tried.  I was able to get into some watches that I had been unable to open before to change their batteries.  I have lots of watches so it would cost me a fortune to have a jewelry store change the batteries or throw them out. I buy my batteries in bulk on Amazon and change my friends, family and co-workers batteries.  In the past there often were some watches that were quite difficult to open but this kit has solved most of those problems.