Stanley fatmax pro box beam spirit levels 3 vial stanley 0 43 681 the stanley fatmax pro level has solid block acrylic vials to provide an accuracy of 05mmm in eight orientations in addition every fatmax pro level comes with a lifetime accuracy warrantythe level is 5 times stronger than other stanley levels thanks to its unique reinforced box beam construction the lightweight aluminium body and sturdy bi material handgrips make handling easy and the precision engineered dual machined