A Drive (Japanese: カセットCassette) is a type of held item introduced in Generation V, used for changing the type of Genesect's signature move, Techno Blast to the corresponding type of Drive.
In Black, White, Black 2, and White 2, they are obtained by showing Genesect to a certain Scientist at the P2 Laboratory. The Burn Drive and Shock Drive are obtained in Pokémon Black or Black 2, while the Douse Drive and Chill Drive are obtained in Pokémon White or White 2.
In X and Y, the Drives can be obtained by showing Genesect to a Hiker at the Fossil Lab in Ambrette Town. He says that he got them from an acquaintance of his in Unova.
A cassette to be held by Genesect. It changes Genesect's Techno Blast move so it becomes Electric type.
In the anime
All of the four Drives appeared in the anime in the movie Genesect and the Legend Awakened attached to the members of the Genesect Army, with the exception of the Red Genesect. While in the movie it was used with the same purpose of changing the type of Techno Blast, it was also the key item to tell each Genesect apart, with the one holding the Douse Drive having a different personality from its group.
It wasn't shown or mentioned in any point of the movie, that Genesect could switch or take off the drives.
In the manga
In the Pokémon Adventures manga
Colress battled Lack-Two's Dewott using a Genesect with apparently no drive. After being severally taunted, the scientist used a Shock Drive to put the Dewott at disadvantage with the legendary Pokémon.