Size: 18.9 mm, 59 EU, 9 US; Interface: Bluetooth 5.4; heart rate monitor; body temperature; Battery capacity (mAh): 18.5; Operating time (days): 7; Material: titanium; Waterproof: 100 WR / 10 ATM; Dustproof & waterproof: IP68; Width (mm): 7; Thickness (mm): 2.6;