Use the Apple Watch SE 44mm to stay in touch. With its integrated GPS, gyroscope, and accelerometer, you can monitor your progress and measure your workouts. Use the ECG app to monitor your heart rate. Additionally, the 40mm watch has a battery life of up to 18 hours. 32GB of ROM 1GB of RAM Display size: 1.7 in. 44 M in size Li-Ion 296 mAh battery