A simple reference panel to remind you which way the nuts need to be spun to level your print bed. I have attached STLs for left and right handed threads.
Right handed threads will be 'Up-Down' or 'Close-Open'.
Left handed threads will be 'Down-Up' or 'Open-Close'.
It's really up to you which you use and how you think about it.
Generally you will probably want 'Up-Down', especially if using a Wanhao Duplicator i3 like myself.
Apologies if I have gotten any of this wrong - I rushed to finish this on my break.