Stanley fatmax i beam levelsl 3 vial stanley 1 43 558 the stanley fatmax i beam magnetic level range provides the ultimate in terms of overall strength and performancethey are fitted with solid block acrylic vials that have been machined to exacting tolerances to ensure that the movement of the bubble is smooth and comes to rest quicklythe stanley fatmax i beam magnetic level range have a small magnifying area in the centre which makes reading the position of the vial easierit has rubber e