- Accessories: USB charging cable - Accessories: Charger - Accessories: Main unit/band - Accessories: Spare band [Note] A subscription is required to use this product. Without a subscription, you will not be able to access any data. [Note] This is the popular healthcare tracking band WHOOP (https://www.whoop.com/jp/en/) in the US. It is the WHOOP 4.0 version. Unlike Apple Watch or Garmin, it doesn't have a display; you view the results on a smartphone app. I have been using it for a few months, and it is in generally clean condition. Operation has been confirmed. It monitors: - Strain - Recovery - Respiratory rate - HRV - Sleep duration - Sleep efficiency (sleep duration / time in bed) - Sleep score (a score calculated by considering all related values) etc. Unlike smartwatches, it automatically detects and records exercise when you start working out. It's the kind of device where data is collected without you even realizing it, as long as you wear it. The battery lasts for about a week.