ABL dial for lead screw

These tiny dials clip on to your lead screw, I use one at bottom and one at top. They make it easy to see how ABL is working during printing and can, for example, indicate when it's time to tram your bed.  The clips doesn't interfere with anything and if you set them too high or low, the bed will just push them to a correct position. I leave mine attached all the time.

Plate 2 contains an optional single-layer max-size circle that I used to check the whole bed. Watching it print while looking at the dial can give you some hints on levelling vs. poorly printed first layer areas.