The release of the Pokémon Go Plus, Nintendo's wearable accessory for Pokémon Go, has been pushed back to September, the company announced today on Twitter.

Nintendo originally planned to release the Pokémon Go Plus in late July; the game, which is free-to-play, launched earlier this month. The company did not give a reason for the delay, but an educated guess is that the phenomenal success of Pokémon Go caused Nintendo to take more time to make enough units to meet the demand for the peripheral. While the game is developed by Niantic Labs, Nintendo is producing and distributing the Pokémon Go Plus.

The Pokémon Go Plus, which is compatible with both the Android and iOS versions of Pokémon Go, will cost $34.99. It is designed to allow people to play the game without having their smartphone out — the Bluetooth-based unit, which can be worn as a pin or with a wrist strap, lights up when Pokémon and PokéStops are nearby. For more details, check out our explainer on the Pokémon Go Plus.

Update: A Nintendo representative told Polygon that the company delayed the Pokémon Go Plus not for production concerns, but instead, to ensure that the game itself would work properly with the accessory.

"The delay is due to the preparations for the Pokémon Go application update in order to optimize Pokémon Go Plus," Nintendo said in a statement. "In order for us to offer new experiences to play Pokémon Go with Pokémon Go Plus with a quality level high enough to satisfy as many people as possible, we decided that it is necessary to take enough time for the completion. We ask for your understanding."