Swiss Tech Aluminum Levels have a rigid aluminum frame which assures durability and accuracy. Top read window for easy readings, cats-eye green vials. Level accuracy of 0.001 in./in. (1.0 mm/m),Its corrosion-resistant aluminum frame is durable to ensure a long working life, and that frame is protected by shock absorbing end caps if the level is accidentally dropped. The level also comes equipped with durable acrylic vials for easy reading at different angles as well as a top read window allowing the user to stand over the work to view the vials. Marking cuts, centerlines and drill points is simplified with the level's ruled working edge.