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The trainers here use Rock type Pokémon so Suicune or the Red Gyarados will come in handy, so will Feraligatr and especially Meganium, any other water or Grass type will be good though, the first trainer can be beaten with a flying Pokémon easily.

Brock's tactic is to wear down your Pokémon with many Pokémon but if you have a Pokémon that is super-effective then it's easy to cut down his many weak Pokémon. Watch out for Kabutops, it knows Giga drain

[edit] Trainer

• Camper Jerry
  • Sandslash (lvl. 37, 1291 EXP) and 740

[edit] Leader

• Leader Brock
  • Graveler (lvl. 41, 1176 EXP)
  • Rhyhorn (lvl. 41, 1185 EXP)
  • Omastar (lvl. 42, 1791 EXP)
  • Onix (lvl. 44, 1017 EXP)
  • Kabutops (lvl. 42, 1809 EXP), 4200 and Boulderbadge