Use a pair of flange Line-Up Pins (FLUP?s) - each sold separately ? in conjunction with a torpedo level to set precise two-hole angles for proper horizontal flange alignment. Con-shaped end pieces automatically center in bolt holes (fits bolt diameters 5/8÷ to 1 7/8÷). As the flange heats up and expands during welding, each FLUP will automatically adjust to maintain a perfect and level alignment. Stainless steel standard.