581 Series Magnetic I-Beam LevelSquare it away: advanced I-beam-frame design ensures accuracy. Tri-vial versatility makes it possible to get plumb, level and 45° angle readings. Top-mounted level-vial window provides a convenient, second vantage point. Magnetic base enables hands-free use on ferrous-metal materials. Level Type: Carpenter/Mason; Leveling Axis: 45°; Horizontal; Vertical.