Removes the difficulty of flange aligning and squaring ,Tool holds a square in the needed position without tying up one's hands ,Base is notched at either end for ease in aligning on the center line of the pipe ,Two 25-pound pull, cast-in magnets for holding either a flat horizontal or vertical position ,Base accepts either leg of a standard or combination square and works on pipe diameters from 1" on up, requiring only the extension of the legs of the square being used to accommodate larger diameters