Stanley 43-048 48-Inch ProLevel I-Beam Level
I-beam/box-beam construction. Level accuracy of 0.001 in. /in.  (0.1 mm/m). Powder-coated frame withstands nicks and is comfortable in hand. Machined leveling surfaces improves accuracy. Low-profile, shock-absorbing end caps stand up to heavy use. Easy-view vial covers designed for effortless reading. Rare earth magnets, which are twice as strong as basic strip magnets, are built into the level for stability.