u/po-laris

>Mantle height: 12.5" for 14" shelf depth max.

I'm interpreting this as "a mantle shelf that sticks out from the wall, above the fireplace, by a 14" horizontal distance should have its bottom edge at least 12.5" vertical distance above the top edge of the fireplace's opening."

Did I get that right? If so: isn't 14" way too deep for a mantle to stick out? It seems like an odd number.