Nortools Vernier Caliper Slide In Travel Case. Two small cylindrical magnets (12x1.8mm each) help hold the calipers in place, there is a small lip near the end of the shaft that snaps-in & locks the calipers in place.

I'm a traveling service tech for automated manufacturing equipment and I always hated how much dead space the original case left in my toolbag. Now it fits into a sleeve/pocket inside my toolbag without getting beat up.

It's hard to describe how satisfying the click lock in is.