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, but if not VERY evenly seated in the hole, you will break feathers and even wedges (I broke several). I feel that they are actually a bit too hardened. I split rocks that were three feet in diameter by drilling holes three inches apart using many feathers and wedges.

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.

...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.

These are effective but the o-rings are crappy that hold them together. I had to keep taping them together with electrical tape. Would have been 5 stars with better o- rings.

The concept of these devices is that they split rocks by applying pressure from the inside going out. These wedges are small but can exert an amazing amount of power. On small granite rocks (less than 3 feet in diameter) buried where I had to dig a trench they easily cleared the ends of boulders. On larger boulders the effect was not as clear cut (pun intended). With one boulder where a path was to go, the top 11 inches of it were in the way. The feathers/wedges were able to break off dinner plate sized pieces 1 to 3 inches thick. This particular boulder is at least 5 feet across and goes down as far as i wanted to dig. Chipping off the top of this rock was/is the easier way to go. Drill 5/8" holes about 4 inches apart and insert the wedges. Tap them with a good sized hammer (at least 20oz.) and work around the wedges from one to the next. They work better when they all are engaged equally. They will make a ringing sound when they are well seated and hit with the hammer. When the ring turns to a thud you have cracked the rock at that point. Breaking a really big rock would require enough wedge/feather units to go across the diameter in no more than 4" spacings. More holes and wedges make things work better. I'm not sure how big a rock/boulder these will break. I have used other methods for large boulders (pickup size) but they require expensive equipment and chemicals ( rock splitting compounds)

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