In reply to Thegypsy:
There is a grade system for Trad, another for Sport, and a couple for Bouldering.
(If you're not aware what these different styles ask, please ask).
Trad grades have an adjectival part (Diff, HVS, E4 etc) and a (British) technical grade (4b, 5a, 6c etc).
Sport grades have just a (French) technical grade, which looks a lot like the British one from 6a up, but also as optional + levels (4, 4+, 5, 5+, 6a, 6a+, 6b etc)
Bouldering has V grades and/or Fontainbleau grades.
So 6a Sport climbs are (roughly) equivalent in technical difficulty to 5a Trad climbs.
Simple !! ?
Rug