Aurifil large spool
I always remind quilters that though the Aurifil spool seems expensive, the yardage is much more than on lesser brands spools so you get more sewing for you money. The weight also means more sewing time per bobbin and more accurate 1/4" seams because the fine thread takes up less space in the seam. And the thread is much "cleaner" resulting in less dust in your machine. Love Aurifil.