What you are seeing is my desire to make sure my dual z axis is leveled every time. I use a Lerdge controller with separate Z steppers, which made this much easier to maintain leveling between each side every time.

Hardware includes:
4 x M2*12mm socket cap screws
4 x M4*10mm button cap screws
4 x M4 tnuts
4 x M2 nuts
I used these SPDT switches:
https://www.amazon.com/gp/product/B07MW2RPJY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1