I never write reviews but honestly I could fill up all 5000 words on how Gripedge saved my butt big time. I had a self-inflicted spark plug mishap in a back facing cylinder. I had an auto machinic come out and couldn't get it, mentioned gripedge and I remembered the name - he didn't have the set of course. After trying traditional square extractor and spiral extractor I thought I was stuck having to take the head a part. Then comes Gripedge. I bought the #6 extractor, it came in a few days later. I used an aviation drill bit that I cut down to exact length I needed, just enough room to get my drill at the back of the engine. After a small pilot hole, I put the Gripedge extractor in and did as instructed. First try it caught on, I Could feel it and knew it was working. Sure enough a few minutes later and that baby popped out. I audibly screamed in success. Something that I spent hours upon hours agonizing over was finally out. I had already invested a few hundred bucks into this ordeal before turning to Gripedge. My only regret is just buying the #6 extractor, I wish I would have got the set as I 100% will use nothing but a Gripedge extractor for any future extraction need.