Depth gauge to radius caliper adapter

I need a radius caliper to measure some big round corner, but they are too expensive. This simple adapter can be attached to depth gauge and use them as radius caliper, It cannot output the value directly, but CAD can help to calc the final result.

There are 2 version of this adapter.

Outer : to measure the round corner from outside. Jaw distance = 50mm

Inner: to measure the round corner from inside. Jaw distance = 20mm

demo : https://youtu.be/EFTBRwbvtkY 

Available in 2 versions, one to measure from outside, one to measure from inside of the round corner/object.