“The cue tip on break cues must be made of leather with no non-leather materials added to the contacting surface.”

Apparently this rule does not apply to jump cues, as it looks like the BCA Leagues are only banning the use of phenolic tips on breaking cues, so if you own a Predator Air or any other jump cue with a phenolic tip, you can continue to use those in league play.  Break cues like the crazy popular 27oz Heavy Breaker though, are now officially against the rules.