The latest version of the Pokemon Go app on iOS and Android supports the new Pokemon Go Plus device, which costs $35 in the US, £35 in the UK or AU$50 in Australia.
The device will vibrate and turn green when you are near a Pokemon that you have caught before, and yellow when it's a creature you haven't caught before. Tap the button to try to catch it, and if it blinks several colors, then you have succeeded. If it turns red, then you failed.
When the device glows blue, it means you are at a PokeStop and can tap the button to collect Pokeballs, Berries and Potions among other possible items.
