Bed bracket 12,5mm, for MK2A bed clones that have mounting holes spaced 320mm.
Did you prepare your parts for 300x300 MK2A bed ? did you found out that your chinese clone bed does not have the spacing 325mm but 320mm?
This should help.
I had to move the screw to the side because of collision with the thumb nut, and i added second screw for symmetry - should hold well enough with just one on side and one on the top.
I added bed leveling knob, tested - all fits and works OK.
The nut is to be pressed in with soldering iron.