I would get the one with the external probe. That wasnt available when I bought mine
A few things to keep in mind. Exact measurements are hard to get. Say for instance you measure 5 areas on a panel. The chances you are going to measure the EXACT five same spots are slim. Also almost all gauges have some margin of error which can throw readings off slightly by a few ulms. Use the gauge as a generaly guide to see areas of paint's thickness, not an exect measurement.

A few things to keep in mind. Exact measurements are hard to get. Say for instance you measure 5 areas on a panel. The chances you are going to measure the EXACT five same spots are slim. Also almost all gauges have some margin of error which can throw readings off slightly by a few ulms. Use the gauge as a generaly guide to see areas of paint's thickness, not an exect measurement.