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

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.

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

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

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.

first time use I had no problem splitting a stubborn boulder on my backyard. very easy to use, works as intended even for a completely newbie like myself.

I've split a lot of granite with these and they hold up well. Drill your holes deep and listen to your rock. It will tell you when it's going to break.

These work like a charm!Items needed:1. Feather and wedges2. Sledgehammer and regular hammer for tapping in3. Rotary hammer drill4. 2-4 good Concrete hammer bitsAnd help lighting your boulders out. These work 1000%If you can see or find the rock veins great, if not these still work great.Drill holes about 4 to 5in apart in a line , try and grab a side one too, not required, and then tap wedges in. Work down the line then back and then sledge drive them as the get down - then boom - your rock is split. Easy day.