30–31 yards inner length is about 19CM (no elastic)

Style: vest style

Product Material ：ABS+HDPE

Collar: Turn-Down (Lapel) Collar

Package internal structure: zipper pocket

Smart Watch – Heart Rate, SpO₂ Tracking & Sleep Tracking Color:Black Silicone 30–31 yards inner length isProduct information: Display screen: 1. 3 inch color screen TFT 240*240 Main chip: Nordic52832 Blood oxygen chip: OSRAM (OSRAM) 2703 Blood pressure type: air pump, airbag type true blood pressure Air pressure sensor: nonlinear, high precision air pressure sensor System: Android4. 4 and above, iOS8. 2 and above Bluetooth: 4. 2BLE (low power consumption) Strap: TPU strap Battery capacity: 200mAh Battery standby: upto 7 days Body Temperature Monitoring,