White Dial Sharp, clear dial graduations Knife-edge contacts for both inside and outside measurements One hand use with the thumb-operated, fine adjustment roll Hardened stainless steel bar, measuring surfaces, rack, gears, and depth rod, Manufacturer: Starrett
Sharp, black graduations on no-glare bar Inside & outside measurements One-handed use w/thumb-operated roll Lock screw for holding sliding jaw in place, Weight: 0.8 lbs., Manufacturer: The L. S. Starrett Co