1.9 HD display Heart rate measurement Sleep detection Sport mode Bluetooth call The most rugged and capable Watch ever, designed for exploration, adventure and endurance. The watch strap use durable and soft silicone, prevents skin from irritation; flexible, lightweight and very comfortable to wear. Sweat & water resistant. An essential and versatile tool that fits on your wrist, Watch Ultra packs incredible capability into a surprisingly small space. Screen: 2.05 Inch TFT LCD screen Bluetooth version: Bluetooth 5.2 Compatilbe: IOS 10.0 or above/ Android 5.0 or higher. Liquid Silicone Strap 260MM*20MM*2.5MM