A strong magnetic edge holds these torpedo levels to any ferrous metal surface. The solid 9 aluminum frames are JobSite ToughTM. V-grooves on the frames fit the curvature of pipe and conduit making it easier to get them level. The SurroundView® vial enhances readability with 3 vials to read plumb, level, and 45° angles. Model JL-5500M-GLO has the patented Glo-View® vial which enhances readability in low light. The Glo-View can be recharged in natural sun light or with electric and battery light sources. Made in USA.