Swanson’s flagship ‘built-like-a-tank’ monster- The Box Beam Level! A super-heavy-duty aluminum frame houses industrial strength acrylic block vials and is finished with Super Shock® end caps made from a proprietary polymer/rubber blend. The deep V-groove channels allow the user to work with both round stock and squared corners, while the available magnetic version has been loaded with incredibly strong rare earth magnets, using IMS technology™ Superior-precision, multi-ring vials indicate drainage pitch for plumbers and landscapers and are accurate to .00050 in.