Stanley 42-480 48-Inch Professional I-Beam Level Heavy-duty aluminum I-beam construction provides rigidity and accuracy Level accuracy of 0.0015 in. /in. (0.15mm/m) 360-Degree vials set directly into frame never need adjustment Large, clear acrylic vial covers and top-read center vial ease readability. Yellow powder-coated body with high-visibility accents easy to spot on job site Limited Lifetime Warranty