Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2605376.

This attaches to a Neiko Digital Caliper (0-150mm), extending the reach about 145mm. I just use tape to secure it in.

Print out a mirrored version to get the bottom caliper jaw.

What would you want this? Dunno, I needed it to measure how thick my head is for a costume.

Edit: Added a holder to glue on the Neiko Box, giving the extenders a place to slide in. It should be glued to the "V" groove on the box. It'll sort of snap into the groove, as it's kind of a tight fit.