Operating system [Proprietary OS] Memory storage capacity 4 GB Special features GPS Battery capacity 451 Milliamp Hours Connectivity technology Bluetooth About this item 【Bluetooth Calling】HONOR WATCH 4 can make and receive calls when connected to Bluetooth.HONOR WATCH 4 also supports quick reply to text messages. Whether you are working out or driving, you will never miss any important messages. 【Fat by grams】HONOR WATCH 4 by utilizing an advanced fat-burning algorithm, we convert calories into grams, making it easy to understand and enhancing the efficiency of your fat burning efforts. 【451 mAh,14-day Long Battery Life】HONOR WATCH 4 with a built-in 451mAh battery, HONOR WATCH 4 utilizes an intelligent scheduling system to efficiently manage the operation mode of each chip in various usage scenarios. With a battery life of up to 14 days under typical usage conditions, it ensures long-lasting durability and worry-free daily use. 【5ATM Waterproof Smartwatch,All-day Blood Oxygen Monitor】HONOR WATCH 4 comes equipped with SpO2, heart rate, sleep, and stress tracking capabilities to help you monitor and manage your health effectively. 【1.75-inch AMOLED screen,300+ Dials】HONOR Watch 4 features a 1.75-inch AMOLED color screen with a refresh rate up to 60Hz and a 390*450 resolution. The various choices of 300+ dials are available to download, catering to your preferences with different themes.