For the Warn M15000 (15k lbs), last time I checked Warn didn't have a properly rated line direct from them. However, I spoke to a Warn rep at Overland Expo last year, and he said they are working on it. He said I should check out Masterpull if I didn't want to wait for Warn. For the 15k lbs winch, 7/16 steel cable is required, and Masterpull makes 1/2" synthetic line that would be suitable. Might only get 60-80' of 1/2" synthetic on vs. 90' of 7/16" steel cable on the drum, but that's normally enough & one could always use an extension, if necessary. I already have 7/16" steel cable, so I haven't made the swap, as 60+' of 1/2" synthetic + 30+' of 1/2" extension isn't cheap, and I hardly ever need to use my winch as it is.