As far as we can tell, this is a Gear Inspection Gauge made by THE BRISTOL COMPANY of Waterbury, Conn. We do not see a Model Number but the Serial Number is X5381. There are several items to be noted. First, the indicator gauge works smoothly by hand but will not return to zero under its own power. May need lubricating or a new spring or, perhaps, replacement. Second, as can be seen in the photos, the set of gears/shafts on the right side of the box is incomplete. Other than that, it seems to be in good shape and is of robust construction. If you need more info, we’ll be glad to help you get the answers you need. Comes in the original wood box.