Uk used Apple watch series 4 40mm GPS Cellular

S4 with 64-bit dual-core processor (Up to 2x faster than S3 processor)

Electrical heart sensor (ECG app)

Water resistant to 50 meters1

LTPO OLED Retina display with Force Touch (1000 nits brightness)

Wi-Fi (802.11b/g/n 2.4GHz)

Bluetooth 5.0

Optical heart sensor

Improved accelerometer

Improved Gyroscope

Ambient light sensor

Capacity 16GB2

All ceramic and sapphire crystal back