working at a shop for hte past few months it blew me away at the different poundage for the X system the tippet and leader companies use. so from what i have gathered the manufacturers are using the x system too rate the diametre of the tippet on tehre tapered leaders and there tippet spools too keep every the similar... and the biggest difference i have found is what you see iceman, pretty much all leaders and tippets have the same diametre for 3X or whatever use wish too use as your control... but! the poundage rating can be off from company too company by as much as 3 or 4 lbs. we have about 5 or 6 different comanies in our shop and on one 5x tapered leader pack the difference was huge ranging form 2.5lb too 4.4 lb depending on what tippet you use with the rest in between like 2.7, 3, 3.4 , 4.0 etc. long story short its best too buy the same leader tippet material as your leader so you dont have a huge difference in the LB test... its best too scan all teh packs by every company and pick the "best" for yourself... its not suprising either that some of teh cheaper stuff is the weaker material while the expencive companies are the tougher material with teh same X grade... hope that helps dude