Powers up not very effective moves.
Tinted Lens is an ability that allows the Pokémon to deal double damage with moves that are "not very effective" against the target. This means that if a Pokémon with Tinted Lens uses a move that would normally deal reduced damage due to type advantages, the damage will instead be doubled, effectively negating the type disadvantage. This ability can be particularly useful for Pokémon that have a diverse movepool and want to maximize their damage output against a variety of opponents.