Machinist's Level with Ground & Graduated VialGround and graduated main vial The base of the level features an involute groove running the length of the base, which provides a reliable seat for round work Cross test vial Vial is adjustable to a positive setting and is housed in a satin finished brass tube with a friction fit closing cover to prevent breakage Main level vial has graduations that are approximately 80 90 seconds or 0. 005" per foot (0. 42 mm per metre) Height: 2 3 4" Length: 12"