One piece. For an additional 100 yen, shipping via Yu-Yu Mercari Bin is possible, so please comment if you'd like that. Specifications: Usage time: 300 hours Standby time: 300 days Waterproof: IP67 Linking method: Bluetooth 4.0 & ANT+ Compatibility: Garmin, Tom's ANT+ sports watches... Garmin, Wahoo, Bryton ANT+ bike computers Online games Zwift, Tacx, Bkool - Supported devices: Cycling apps, trainer software, stopwatches Note: The cadence speed sensor is in cadence mode by default. For the speed sensor, the user needs to change the operating mode.