Osborne Rules are made of anodized aluminum and are tempered to stay straight.
60-SE, 802-36, 802-60

Swanson Straight Edges are made of high-grade aluminum alloy with high visibility, thermally fused, yellow powder paint finish.
Lightweight and strong, with black thermo-bonded gradations.
AE-141 36" Rule (1-1/4" wide, non-glare finish)