Tried to search these bases and couldn't come up with anything, (probably not looking in the right place). Anyway, a friend mounted these bases for me quite a few years back. They are Baer bases. The front base shows markings of, front and short. The rear base merely says Baer. Very clearly the rear base is much higher then the front base. I was looking into a trajectory compensating turret for my scope and on the order form they inquire if I'm using tapered bases. Also, if the bases are 20MOA or 40MOA. How do I find out what I have? Nope, I can't contact the person that put the bases on. He lives in another sate and can't find a phone number.