The 624M Series is a
two-sided metric ruler. It is 1 1/4" wide, .032" thick,
and is available in
12", 18", and 24" lengths. The front has inches in 32nds
for the first
inch and in 16ths for the rest on top and picas/half-picas on the
back has two metric increments going in opposite directions.
The top increments
are in millimeters and the bottom is in half-millimeters.