The mainlines can be 75 or 80 feet long. That gives you enough room to space a dozen decoys 6-7' apart. Then you clip separate anchor lines to the main line. I will be dissenting voice and say if you are going to scrimp on something, don't do it on the mainlines. Get some 1/4" or 3/8" diamond braid and you never have to worry about upgrading. Ever.