Lufkin, 6' Red End, Extension Wood Rule Inside Read, With Graduated Metal Slide Rule That Extends Up To 6', Slide Rule Runs Under Friction In T-Slot & Stops At Each End To Prevent Slide From Falling Out, Both Sides & Both Edges Are Marked, Graduated To 1/16th Of An Inch, 16" Stud Center In Red, Regular Outside Markings.