I removed a hardened bolt on my mountain bike. I found out that the screw extractor is a screw extractor, so I went with a cheap Chinese manufacturer of an unknown brand. Big mistake. After 45 minutes I was left with a useless tool and a big disappointment. After doing a little research I came across this MFG kit from Irwin which I know from previous purchases make quality tools. Well it only took 2 minutes to get my stripped stud out. Some thoughts. The exercises were fantastic. No problem with cutting the bolt; I just used a real slow speed drill bit and added some elbow grease. The puller also worked better than expected. After drilling, I inserted the extractor and used a ratchet to turn it counter-clockwise with a SLOW CONSTANT force. The screw came loose, which was tightened with a torque of 10 Nm. Do not use an electric/cordless drill with suction. Use a ratchet and let the torque turn off. Result; Don't skimp on tools. A quality set will save you time, money and effort.