HIYD is a compact sensor designed to add health and activity insights underneath the wristwatch you already wear.
- Discreet Watch Attachment: The planned 2.7 mm-thick, 25 mm-wide sensor uses microsuction to attach beneath a compatible watch caseback.
- Optical and Motion Sensing: Red, infrared, and green optical sensing combines with an accelerometer for heart-rate, sleep, activity, and recovery insights.
- Companion Health App: The iOS and Android app brings measurements together with nutrition logging, cycle tracking, and optional AI coaching.
- Extended Battery Options: The maker specifies up to four days of sensor use, or up to twenty days with the optional Battery Band.
- Flexible Wearing Accessories: A Soft Band and optional caseback and NATO-style adapters support different watches and daily activities.
