STABILAs 4 foot type 196 M spirit levels feature extra-rigid rectangular box beam aluminum profiles with reinforcing ribs, recessed rare earth magnets, milled measuring surfaces, ergonomic hand holes, removable shock-absorbing end caps with anti-slip wall grips, and very accurate matched vials that ensure all plumb readings are the same when leveling in normal and reverse positions. These hand tools are the most popular STABILA box frame spirit level tools in North America!