Hi NormK,
You place the bar across the bottom of the mower running from bottom of rear roller to bottom of front roller.
You then press the bottom shaft on the bottom of the HOC tool, I have some blue tape on it for demonstation, the top shaft moves up and you locate the screw on the top of the bed knife.
It gives you a 100% accurate height of cut digital measurement.
This is much better and easier to use than the bar that people have with the bolt/nut you adjust to the height you want.
Digital readout from from 0 to about 26mm.
Cheerz
Hi Ken,
what do you use it for?