Lufkin HX46 6-Inch x 5/8-Inch Wood Extendable Folding Ruler

Graduated slide rule extends up to 6". Slide rule runs under friction in T-slot. Stops at each end to prevents slide from falling out. Has hook; zero falls at inside of hook, for distance measuring. Marked both sides and both edges. Graduated to 1/16ths of an inch. 16" stud centers in red, regular outside markings.