Big Foot LA-DCBWC Dual Line Chalk Box with Chalk You can also use a different color for your high walls, rake walls and short walls. If you need more chalk of the same color you can usebothsides of the Big Foot Dual Cavity Chalk Box. The Box has 125' of line in each side of the box for a total of 250'. Changing lines is easy with the replacement spool which has the string guide and hook already on it. The Big Foot Dual Cavity Chalk Box is made of light-weight aluminum with durable gears for longer lifeand fits in your nail bag. This is an O.E.M. part