A Mannheim rule virtually identical to the Post 1447, not surprisingly. The only difference is the maker's name and the weird little symbols next to the A and D scale names. It's pretty obvious what the one next to the A scale is supposed to represent, but the one next to the D scale, i've no idea. Mostly because i don't have the rule in front of me right now and i'm too lazy to go find out what it really says. You care. You care a lot.