The spool is an easy way to get more line without having to do your own winding, although you can buy a lot of line for what the spool costs. My reason for not giving this five stars is that it doesn't include the parts that were dying on my Yardstick which were the spring (It's not attached so is very easy to lose), and the cover for the spool, which after enough bumps on concrete sidewalks gets sanded down and disintegrates. Those pieces have to be ordered from a site that American Gardener sends you to. The entire assembly including the spool, housing, spring and cover, sells for about $7, but it costs $8.95 to ship.Incidentally, I had a bunch of .065 line left over from my previous weedwacker, and it works fine on my American Gardener assembly.