IRWIN Tools 2000 Box Beam and Door Jamb Level Kit, 78-Inch / 32-Inch (1794103) Continuous edge increases level durability to ensure accuracy over time, protects center vial bubble, and allows for continuous scribing. Plumb Site offers dual-sided, undistorted viewing in the plumb position and easy, more accurate plumb readings. Retractable end-caps allow for scribing into and through corners, increasing work efficiency.