In the things I bought this weekend is this metal Miter-Master, made in Minneapolis Mn. pat. pending. What is novel to me, is it was a long ago give away, or customer premium for the MoorMans livestock feed company. I worked for them a number of years. The base has screw holes, so is to be mounted to a board? I am guessing to set angle of rafters? Incorporated into it are two more tools. a dowel and drill diameter gauge, the tapered slot. There is also a marking gauge function, (Insert point into hole) marked from one inch down to 1/8 inch. Back in the days when companies gave away things as incentives. Going on the wall above my woodworking table.