I was expecting the spools to fee out 2 lines at the same time. The spool that the unit came with had 2 lines on the spool. I have not tried the ones you send me. I don not know if I have to have 2 lines working at the same time. It might have something to do with, possible vibration if there ae not 2 lines being used. I will try one very soon, and if there is a problem, i will let you Know