OPPO Band 2. Display type: AMOLED, Display diagonal: 3.99 cm (1.57"), Display resolution: 256 x 402 pixels. Device type: Armband activity tracker, Form factor: Rectangle, Product colour: Black. Heart rate sensor type: Optical. Battery life: 14 day(s), Battery capacity: 200 mAh, Charging time: 1 h. Weight: 20.4 g, Width: 45.3 mm, Depth: 29.1 mm