Klein Tools 901-6 Wood Folding Rule, Outside Reading

It does. Red stud center markings fall every 16 inches along the black-on-yellow scale, so you can mark standard 16 inch on-center stud or box layout straight off the rule without measuring each one.

A folding rule stays rigid when extended, so one person can measure up a wall, across an opening, or into a panel bay without a second hand or a hook to catch on something. The 901-6 is 6 feet (1.8 m) of hardwood, 0.75 inch wide, with riveted locking joints that hold the sections straight. A tape is better for long runs and coiling into a pocket; the rule wins where you need it to stand on its own and where you want stud centers marked for you.

No. The 901-6 is an outside-reading wood rule with no slide extension, so it is not the tool for inside measurements of window openings, duct, or door frames. If you need to take an inside dimension off the rule itself, you want an inside-reading folding rule with a brass extension instead.

Outside reading means the graduations run so you read the scale on the outer face as the rule is unfolded away from you, which is the common layout for general layout and framing work. The 901-6 is engraved on both sides and both edges, so you get a usable scale no matter which way the rule sits against the work.

Graduated to 1/16 inch in SAE (inch) units, engraved rather than printed. Engraved marks stay readable after the painted surface takes abuse, which matters on a rule that lives in a pouch. There are no metric graduations on it.

Extended it runs 72 inches; folded it is a flat stick 0.75 inch wide by 0.675 inch thick, and the whole rule weighs 5.3 oz (150 g). That drops into a standard rule pocket on a pouch or bags with no bulk.

They lock. The 901-6 uses riveted locking joints, so each section snaps into line and stays there for overhead or reach-out measurements. The riveted construction is also what keeps the joints from loosening and throwing the accuracy off over time.

The graduations are engraved into the wood, not just printed on it, and the rule carries a clear abrasion-resistant coating over the yellow finish. Scuffing the face does not take the numbers with it.