This 24" JohnsonMagnetic Aluminum Box Levelcomes equipped with solid block acrylic vials that won't fog, leak or break, & the shock absorbing endcaps protect the level when dropped, ensuring it stays accurate for life. When working in poorly lit areas, the "SurroundView" vials reflect ambient light to keep them easy to read. This box level features strong rare earth magnets that hold the level securely in place on flat or round ferrous surfaces. Johnson Level Model No. 1721-2400.