LThe primary difference between a ruler and a straightedge is that a ruler is a measurement device whereas a straightedge is a tool for drawing a straight line or checking the flatness of a surface. Nowadays that distinction is generally invalid, it’s all about how you use it.
Anodized aluminum ruler with durable printed scale accurate to 0.7mm/m
308 Straight Edge
Contractor grade anodized aluminum with printed scale accurate to 0.7mm/m
630 Telescopic Aluminum Ruler
The solid construction maintains the accuracy of the ruler while the telescopic capabilities make it a great measuring tool which can be easily stored.