Interesting outside caliper

[Pirate]

At a yard sale I bought a stainless steel, medical, Pelvimeter (outside caliper)
Looks like it might come in handy. Opens and reads to 18"
Thinking might be handy for measuring bowl wall thickness, where you might not be able to get a caliper, that doesn't have a scale, out, to measure the thickness, without loosing the setting.

[Arlin Eastman]

I really like it and think for turning more of them should be available.   In working with spindle working it would never catch and I will have to think about welding some on mine.