Rick -

The X factor is a size - subtract the X from .011 inch and you get the size of the tippet material. For example, .011 minus 1X is .010 inch, .011 minus 3X is .008, .011 minus 5X is .006, etc. That is an industry standard, as I understand it, but that doesn't mean every tippet is going to be right on the standard. Take a micrometer to tippets of a given tippet size even from the same manufacturer and you will likely find some very nominal variance.

The two 1X mono tippets you mentioned are pretty close in rated break strength at 13# and 12#.

Fluorocarbon is an inherently weaker material. It is has some advantages over mono but strength is definitely not one of them, as evidenced by the 8# rating on the 1X fluoro. It has some disadvantages, also.

I like Rio Powerflex and use it almost exclusively for tippets. I did pick up a whole bunch of Dai-Riki 9' 1X leaders at www.sierratradingpost.com a while back for $.55 each. They are great for fishing big nymphs, especially tandems - and I can't make my own knotted tapered leaders or furled leaders for 55cents each !!! Three dozen for under $20 !!!

John