IRWIN Tools 2500 Box Beam and Door Jamb Level Kit, 78-Inch / 32-Inch (1794073) Thick-walled high-grade aluminum frame provides extreme durability and resists jobsite wear and tear. 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.