I had to put a new battery in my wife's cheap Timex.  Using this kit  I was able to use the included knife tool to get the back off BUT I was not able to get the back cover back on the watch. The watch requires a press for that so the kit is missing one crucial piece.  I threw my wife's Timex in the trash. In this instance my buying the kit was a waste of money. The tools in the kit seem just fine and the knife was especially durable. I thought it would break because the back cover was really hard to get off. The knife did not break. It worked just fine. I also used to the adjustment tool that is used for the back covers that have the 2 slots.  I was able to take the back cover off my watch easily with that. Originally before (before buying the kit) I tried putting a small flat blade screwdriver and using a small hammer to try and tap the cover in a counterclockwise motion to get the cover off. It didn't budge and I didn't want to damage the watch. With the tool I was able to take the watch back cover off easily !