B/W: A Pokémon hold item that promotes Sp. Atk gain on leveling, but reduces the Speed stat.
This item did not appear in any previous games.
Power Lens are an item introduced in Generation IV that adds 4 Special EV points to the Pokémon holding it when it gains Experience Points, regardless of the EV point(s) it normally gains from the opposing Pokémon. While it is held, it reduces the Pokémon's Speed stat by half.