I bought this set to pair with a masonry bit to break up a 6 foot long and 4 foot high boulder in the middle of my lawn. It's hard work, but I'm going forward with confidence. It's tricky because instead of being off the ground, only the top of the boulder is visible, so instead of removing the whole thing, I knock off the top and just cover it with about an 8 inch layer of clay when I'm at it finished. O-rings are built for tough use, but they can easily break after a few accidental hits, so it's a good idea to have spares on hand. They're easier to pull out, but that's not a problem. The steel appears hardened and very dense. I had no problems with bending or warping. You slide into the pilot hole and after just 10 clicks the section breaks free - talk about a nice sound.