This is the thread that sailmakers use for stitching the panels on sails. It is heavy, bonded "Dabond" polyester thread that will work in most home sewing machines (use a #20 needle). The spool is made for industrial machines so be prepared to wind it onto smaller spools as well as bobbins. Each cone has 350 yards. Suitable for all sailcloth and Sunbrella sold here. Available in colors.