The extractor is somewhat unique in how it works, compared to the spiral and flute traditional types. Read and UNDERSTAND the instructions before using. It worked perfectly for me, but it was a "clean" problem I had - Two bolts on the 3 point hitch mount had sheared off (as designed) due to excess stress on my Case tractor. The bolts were not rusty, the heads just sheared off flush. The first bolt came out using the two steps required (drill then extract) with the extractor. The second bolt actually unscrewed while drilling the hole for the extractor (drill bit is counter clockwise rotation). I think this would work on slightly rusty bolts as well, but it would probably be important to really prep the rusty bolt first with lots of penetrating oil, some sharp taps on it to try to break the rust bond, etc. before using the extractor.
Had a broken bolt in an intake manifold. After several attempts of removing it with an extractor I have up and went and purchased this one. This did not even drill into the bolt after about 30 minutes of drilling and getting no where fast I returned the item and got a refund.
Used the 1/4 bit...first time it broke. Used the 5/16 bit, first time it broke. Followed directions each, used heat and PB Blaster with variable speed drill on low in reverse. Did not work well, after two attempts to return with lifetime warranty, item was replaced. Maybe they only work on soft bolts?
I tried drilling out a grade 8 bolt and this extractor wouldn't even drill into the bolt. I struggled on one bolt for half an hour and I am returning the kit this afternoon. Maybe this kit works well for soft poor quality bolts, but it will not get out higher strength bolts.