The Apple Watch Series 5 includes an always-on display with energy saving LTPO OLED screen and low-power screen driver capable of refresh rates as low as once per second. The always-on display was not included in the Apple Watch Series 4. [1] Additional new features include International Emergency Calling which enables emergency calls in over 150 countries, a more power-efficient S5 processor, improved ambient light sensor, doubling of storage capacity to 32 GB, and the addition of a magnetometer, which enables a compass function.