Measure below the Foot
When making pots on the wheel. I sometimes make the base to thick Or to thin .
Some people use a needle tool to measure the thickness of the clay .

I wanted to improve on this technique and wanted something that I could set the depth

I wanted a  needle tool Which would give me a measured depth
Measuring Below the Foot

The needle tool allows me to set the needle depth below the foot
there is a small indicator on the side of the needle tube indicating the depth below the foot