Pokémon GO Plus +

The Pokémon GO Plus+ is an upcoming device that will operate similarly to the Pokémon GO Plus and Poké Ball Plus. Trainers will be able to place a Pokémon inside the device which will alert them of nearby PokéStops.

Features
The Pokémon Go Plus+ is designed be a sleep monitoring device, due to its built-in accelerometer. The accessory will "track simple information about how long you sleep," said Nintendo's Kazuhiru Maruyama, and transfer sleep data to the Pokémon Sleep app.