From Bulbapedia, the community-driven Pokémon encyclopedia.

Pokémon V-Trainer is an electronic device that allows the player to use Pokémon figurines to battle Gym Leaders or trainer cartridges or another person. The initial system comes with a Treecko level 1 Figurine, a Steven battle pack and the instructions.

The V-trainer does not have batteries initally and requires a screwdriver (to open the battery compartment) and two AAA batteries. When the user first turns it on, he press the bottom right button and then enters his trainer name, which has a limit of 5 letters. He starts off as a level one trainer with unlimited scratch attacks and can only select a training battle until he earns enough points to advance to the next level. There are other expansion packs with a battle pack and two Pokémon. Pokémon figurines come in 3 levels.