This is purposefully a light-duty (thin and inexpensive) tool to help gauge the diameter of a pipe or tube, or anything cylindrical. Simply push it against your object and the indicator will show you how big it is, from ½" to 3 ½" in half-inch increments.

Flip it wide open and it's a 1' ruler.

After printing, put the two halves together and tighten the bolt down to secure the them together. It may be a bit gummy, this was actually intentional. If so, back the bolt out and when you drive it back in it should basically lock itself in place without adhesive. There is a small tolerance that allows the two parts to freely spin with the bolt completely tight; this is not a locking caliper.

The profile is set to print by-object, starting with the bolt. If the bolts and indicator markings are the same material (all parts are addressable in the objects list) then only four color changes are necessary. High contrast colors suggested. Text will be sharp if your material profiles are calibrated for flow ratio and pressure advance, should be clearly readable with default values.

An example of the addressable parts.