Wedge and Feather Shims Concrete Marble Granite Rock Stone Splitting Hand Tools (5/8", 10Pcs)

These work extremely well!

It helps to watch an online video of how to use the wedges and feathers. Get a good 5/8" 2-4 cutter (Star) masonry drill bit to make things go quicker. Do yourself a favor and use at least a SDS Max hammer drill. Space the holes a maximum of 6" apart. The deeper you make the holes the better they will work. Use a single firm tap on each of the wedges in the line of wedges with a 3 pound hammer (bigger is not always better in this case) and give them a chance to work. Work back and forth on the line and listen to the rock break Pounding on a single wedge tends to be a waste of effort. A magnetic pickup tool helps to retrieve any wedges or feathers that fall in the hole. Worked well for me breaking up a 8-12 inch unreinforced concrete slab and some 3-4 foot diameter granite Bolders

Worked well. Broke up a bunch of boulders without too much fuss. The rubber o-rings are a nice touch to keep things together when your fingers are shaking from having run the hammer drill, but those o-rings deteriorate after a few missed hammer hits (my fault). Still, a great idea and they worked well for me. Advice: if you have a bigger section to split, then maybe buy two full sets. At one point I had all of them pounded in (probably didn't drill them close enough to each other) and had to pound away at the rock with a sledgehammer to get those cracks to split all the way. A handful more of them would have made life easier. As for size, I think this is about the biggest I would get, because any larger moves you into expensive bits and drill hardware and much heavier work. I broke maybe 12 cubic feet of granite out of the yard where the Earth was poking through the grass in a few places. Took a few days but these did the job and are still very usable. Wish I bought more though.

Hood would be great if didnt randomly chip off metal chunks.

...you need to educate yourself on their proper use and have the right tools. I read the reviews and did a bunch of online research. I have to large boulders protruding a few inches above ground where I want to extend my driveway. They are way too big for any machinery to move. They needed broken up somehow. I bought a cheap (<$100) Bauer-brand rotary air hammer from Harbor Freight and a set of SDS bits that turned out to be garbage. The Stanley brand bit I bought on Amazon, however, worked awesome. I chose the smaller of the 2 boulders first. It had pretty obvious grain as well as what appeared to be a fault line along the grain. No amount of hitting it with a sledgehammer, however, would break it up. This feather and wedge kit worked IMMEDIATELY, splitting the boulder into 3 large chunks. I haven't gotten to the larger boulder behind it yet, but I'm confident I can break that one up as well.