Mine is homemade. Built a looong time ago with limited tooling and knowledge. I was 11 or 12? When I built it alongside with my dad. It's only a 12 Ton unit but so far, I haven't really needed more.
Back then, I had a little Kubota
B7000, so I built it towable because the Kubota didn't even have 3 pt hitch and certainly not the power to lift it.
Over the years, it had various versions. Started with a small Tecumseh gas engine, which made a lot of noise and really liked gas.
Then, I started using the my homemade backhoe, but it required to have the backhoe there every time I wanted to split wood.
Next, I changed it to a 3 phase 400v electric motor. The best version of it. Good speed and very very quiet.
Later, I bought my Branson and started using the splitter using the remotes of the tractor. Engine running at 1500RPM, give or take. Obviously louder than the electric motor, but still quiet enough you could have a conversation. Barely used any fuel.
By the time my Branson started to stay more and more at the remote propriety, I also got solar panels at home, so I decided to change the splitter back to the 3 phase 400V electric motor. Timing things right, means I can pretty much split wood for free as the solar will cover the power used by the electric motor easily.
During this change over, I went ahead and modified the valve so it would auto return. I did this by changing how the spring actuated on the spool and then used a end of stroke valve I had, so when the cylinder retracts all the way, it dumps the fluid to the tank. The way the spool on my valve was built, I couldn't do it with a mechanical linkage, without deadheading the pump. Also, I made a foot pedal to control it. This really improved the productivity as you now have 2 free hands to handle the wood.
Man, now that I read this post, it quite a story. Sorry for the long winded post.
Anyway, all of these changes and I only have some pictures of the very first use it got in its first version. Can't even see the axe of it but it's on the cylinder side. I've since extended the width of the side "tables".