Apple Watch Series 1, 38mm / 42mm, 8GB. 

Optical heart rate sensor, Bluetooth 4.2, 2.4GHz Wi-Fi only. 

No built-in GPS, NO cellular, ONLY IPX7 splash resistant (NOT swim-proof). 

Max watchOS: 6.3, cannot upgrade to watchOS7+. 

Compatible with iPhone 5 or newer with iOS10–iOS13. Used item, battery aging, reduced battery life. Cosmetic wear possible.

Important Notes:

1. Maximum watchOS version: watchOS 6.3. Cannot update to watchOS7 or higher. Requires iPhone 5 or newer with iOS10 ~ iOS13. Pairing may fail on new iPhones with newer iOS versions.
2. NO built-in GPS: Workout tracking requires paired iPhone nearby. No cellular / eSIM function at all.
3. Only supports 2.4GHz Wi-Fi. 5GHz Wi-Fi networks will not show up. Unknown Wi-Fi cannot be manually added; paired iPhone must connect to that Wi-Fi first.
4. IPX7 splash resistant ONLY. NOT waterproof for swimming or immersion. The old seal on this used watch cannot be guaranteed. Do NOT submerge in water.
5. This is a pre-owned watch. Battery has natural aging, battery life will be shorter. New battery is not included.
6. No ECG, blood oxygen, fall detection, SOS emergency call or barometer. Apps may run slowly.
7. Pre-owned item, scratches and cosmetic marks may exist.