Stanley and a few other tool makers produced beautiful bone rulers, which bear their marks, but I've looked and looked and not found another like this one. There are no readable measures on the bone, but on the both sides of the silver end on are marks for 4 and 5 inches, and then the caliper pulls out to measure 2 inches, with each inch divided into 32nds on the flip side. Probably more of a beautiful thing than a super useful tool these days, but really lovely, and feels pretty great to carry around in one's hand or pocket.
6 3/8" long when open; closed 3 1/2" x 7/8" x 1/8". Structurally in execellent condition with the closure pin still in place, and it closes tight and flush; I have not tried to polish it. The caliper pulls all of the way out, so is also useful on its own measuring tiny things.