Non-rotating, blade-type rods approximately .045" thick x 1/8" wide (1.2 x 3.2mm). By holding the base in one hand, the blade can be turned with the fingers and positioned at any angle relative to the base. The blade does not turn, but moves perpendicularly only, permitting depth measurement of narrow shoulders without the blade rolling off. The micrometer screw is precision ground. Bases and rods are hardened, ground, and lapped. Rods have individual length adjustment. Added features include no-glare satin chrome finish. Graduation is .001". With ratchet stop, no lock nut in case.