fast flight or not, how can you tell ?

how can you tell the difference between a f-f, and a regular string?
 
somebody's got to know.

i put a new string on my bow, it is b-50 and it changed the flight character of my arrow, like maybe it was stiff now, so im thinkin the other string might have been f-f or some kind of hybrid. so i put it back on. and all is good again.    thanks

[mrpenguin]

It sounds like you have a a lower stretch string for the original... and the way you are discerning that is the best method... unless you want to disassemble the string and compair how the two materials feel  

[Bjorn]

FF type string is hard to cut with scissors-needs a knife blade. Dacron cuts easily with whatever ya' got.

[Don Stokes]

FF is also hard to cut with a broadhead, which has saved me from embarrassment a couple of times!

thanks guys.