I have various sizes of these straight edges. I have a label on one stating, Cleform, St Joseph, Missouri They are aluminum. I tried to weight the 8-0" and it weighs approx. 7 lbs which sounds light.
7/8" X 4 1/8" x 6' $75
7/8" X 4 1/8" x 8' $95
7/8" X 4 1/8" x 10' $120 all gone
7/8" X 4 1/8" x 12' $140 all gone
7/8" X 4 1/8" x 14' $160 all gone
I assume they are aluminum, but I'm not sure they are not magnesium.
I'm going to have to check them for markings.