Removing freewheel from MXUS 3000

My single speed 12T freewheel, which came with the MXUS finally failed totally. Now I would like to replace it, but I can't figure how to remove it

I don't remember how I attached it, but it seems to be kinda weird, because it is opposite to a normal BMX freewheel. What is the tool for this particular freewheel and how to use it? Where could I find a replacement?

Attached picture.

Looks to me like you grab the spacer, up against the hub cover. I'm not familiar with this, just my guess based on looking.

Looks pretty obvious to me. I'd take a hammer and flat screwdriver to the hump part over the threads. A few taps should loosen it enough to screw off manually. You also might try a BB tool on it if you have one. Or some big channel lock pliers. if there's another hump on the other side, you may even be able to get a big wrench on it.

This one should fit: http://kinaye-motorsports.myshopify...ories-upgrades/products/12t-x-1-375-freewheel