To use Pokémon Sleep, the new gamified sleep-tracking application for iOS and Android devices, you’ll need the $54.99 Pokémon Go Plus Plus accessory (silly name, I know). It’s a more capable version of the original Pokémon Go Plus accessory that, in addition to working with Sleep, allows you to track your distance and catch Pokémon without having to open the Pokémon Go app.
The small disc-shaped accessory is equipped with a single button in its middle to enable sleep tracking, and it can be used to spin nearby PokéStops in Pokémon Go automatically. It’s also capable of throwing Great Balls and Ultra Balls to catch Pokémon, in addition to your standard Pokéballs.
Update (July 14): Updated article to reflect the launch of the Pokémon Go Plus Plus.