Looking at the line diameters, "leader material" are much thicker, and therefore are rated lower in terms of lbs they can hold....just like NADO said.
I have used raven fluro leaders before when I first started, but spending $12 for 30yards of fluro leader that was same lbs yet thicker..didnt make sense to me.Thats why I wont use drennan, nothing against their quality (they have amazing floats and other equipment) but its extremely overpriced because regular good quality fluro does the same job.
Seaguar INVENTED flurocarbon, their line is made in Japan, and the abrazx line is specially treated for extra abrasion resistance, JUST like the raven and drennan fluro leaders. Yet a 200 yard spool costs $25, and will last you a lifetime of fishing.
Ive had to cut my line because I got it stuck under a log and the 8lb leader I had on would not snap or greak no matter how hard I tried (obviously trying not to snap the rod in the process)