Magnetic, high-impact plastic with folding, central hinge that opens every 15° for greater accuracy when reading posts, pipes or signs. Versatile, can also be used on flat surfaces. Folds flat for easy storage. Includes reinforced, perforated, heavy-duty elastic strap for quick and easy fastening to non-metallic posts. 3 yellow vials will plumb or level in both planes at the same time. Shelf Pack includes 6 levels in a display box.