I strongly recomend people NOT to buy this product I had a $100 watch that I could not close the back cover after I replaced the battery. I thought this tool will save me money and a trip to the jeweler store instead, the very first time I used it, it cause the crystal face of my watch to crack. It cost me $60 to repair it at a watch repair shop. if we considered that I paid $18 for this tool I could have just paid that to any watch repair shop to put the cover back on my watch. Very unsafe tool and useless