R beams are the most robust spirit level tools that STABILA manufactures. STABILAs R beams were developed to withstand the toughest worksite conditions. STABILAs 4-foot R beams feature extremely strong aluminum frames, extra-wide covered measuring surfaces, bridged horizontal vials, removable shock-absorbing end caps with anti-slip wall grips, and very accurate matched vials that ensure both plumb readings are the same when leveling in normal and reverse positions. STABILAs R beams are unlike any other levels on the market. These levels are some of the best products STABILA makes.