Banned Pokemon: Blaziken (With Speed Boost), Deoxys, Deoxys-Attack, Groudon, Ho-Oh, Kyogre, Lugia, Mewtwo, Rayquaza, Latios, Latias, Mega Charizard X, Greninja(With protean).
Banned Items: Charizardite X, Damp Rock, Smooth Rock, Soul Dew.
Besides that, gym rules, all of the clauses apply.
Team preview must be turned on. You may use battle rules to raise to level 100 if needed.
A judge must watch your battle, and you must tell the judge your full team. If your opponent is the judge, you can tell the after the battle.