This a very simple but efficient digital height gauge :
It's made out of a plank of laminate parquet flooring, because this is very stiff material.
The little piece clamped to hold the caliper has a groove to take the caliper.
I have a short and a longer version, here it is the short.
Of course, you use it with a digital caliper in order to be able to set the zero point when touching the table.
Can be used to setup tools or in luthiery, when carving archtop plates, to measure the heights at different points.