Bundle includes 1 Maxi Line Chalk Line and 2 Chalk Refills. The Maxi Chalk Line with Chalk Flask creates a straight guidance line over a distance. Not only is this an essential item in a roofers toolbox, the Maxi Chalk Line can be uses to create an outline of an area, to mark a guide before cutting something, to ensure bricks are being laid straight and much more. The Chalk Flasks simply screw in to the back of the Maxi Line and are ready to use in seconds.