"I have a 15mm bolt head that is stripped, but the packing doesn't state it will grab a 15mm head, only 14mm and 16mm. Is it worth a try?

I have a 15mm bolt that I needed to remove from a Chevy Truck oil pan that was rounded off. I contacted Lowe's customer service and they indicated it would work. I even contacted Irwin customer service for their opinion but it was non-comital. I gave it a shot anyway and it turned out very well. The 5/8 size fit well with a little smack of a hammer and the ratchet was able to back it with a little smack of the handle. The tool cut into the bolt aluminum head perfectly and it came off easily. Make sure that you have another new bolt ready to go as you don't want to put the old one back. Worked very well and quickly. Would recommend for your 15mm Chevy oil pan drain plug bolts. Oh, don't bother with the Craftman bolt extractor set, it does not have the 5/8 tool for the 15mm bolt face.

I have the same problem. A 15mm oil drain plug bolt that stripped. I thought I'd give this kit a try. In my experience, this particular kit was not for me, and did not extract the bolt, or even get close. Was entirely too loose at 14mm and WAY to big at 16mm. I hope that helps.