I can't find another tool quite like this, but it sure is a beautiful thing. My guess is that it is a mitering tool of some sort, and I wonder perhaps if M.Reich was perhaps a frame maker? Whatever the case, I have to think Reich valued it a great deal, stamping it with his (or her) name a total of seven times (!)) and I'd think brought a lot of joy, too, as it is a tremendously satisfying thing to hold in one's hand. Solid brass (I believe brass rather than bronze), it weighs in at 1 lb. 10 oz., making a great paperweight for someone less than handy, like me (who might also use it just for drawing angles and straight lines), but perhaps truly the perfect tool for someone out there!
4 7/8" long measured on the hypotenuse; short sides are 2 5/8" long each; 1 1/8" thick. Shows use but really in beautiful condition.