Breadth Caliper, Martin, 20" Maximum by G.S Online Store

It is solidly built, smooth to open and close with the right amount of tension. The scale on it is definitely not to scale but I use it to compare thickness not to take measurements with it.

This tool works well for measuring thicknesses of larger objects. My wife measures houses and buildings for drawings, tax assessments, etc. One common issue with commercial buildings is that wall thicknesses can vary. This tool allows her to measure at windows and around door frames to get an accurate thickness of the walls. The one negative comment would be that the numbers are very hard to read. Not impossible, just hard.

Good value

It was about 1/2" off in a 5-3/4" measurement.About 1" off in a 7" measurement.About 1-1/4" off in a 15" measurement.This item should not be relied upon to take measurements for any reason.

In other reviews I noticed others said the scale was significantly inaccurate. I found it rather accurate if you use the measurement shown close to the outer edge of the caliper scale. At the extreme outer measurements, such as beyond 35cm it is a bit inaccurate by a couple cm. Overall I am happy as other calipers cannot handle these larger measurements.

What I expected at reasonable price.

Item is as described, except it’s listed as 20” maximum, but measurements are marked in centimeters.

I wasn't sure what I was going to get when I ordered this, but i was pleasantly surprised. It is made of solid metal and suits my needs fine. It isn't exact machining, but its what you get for the price