Model Number: A1553

Storage: 8GB

Initial watchOS: Watch OS 1.0

Latest watchOS: watchOS 4.3.2

Released: March 9 2015

Discontinued: September 7 2016

Weight: 40g

Chipset: Apple S1

RAM: 512MB

Display Specifications:
- 1.5" OLED Multi Touch Screen
- 340 x 272 display resolution at 290ppi

Colours:
- Space Grey
- Gold
- Rose Gold
- Silver
- Chrome
- Yellow Gold (18 Carat)
- Rose Gold (18 Carat)

New Features:
- Digital Crown
- watchOS

Model Number: A1554

Storage: 8GB

Initial watchOS: Watch OS 1.0

Latest watchOS: watchOS 4.3.2

Released: March 9 2015

Discontinued: September 7 2016

Weight: 50g

Chipset: Apple S1

RAM: 512MB

Display Specifications:
- 1.65" OLED Multi Touch Screen
- 390 x 312 display resolution at 303ppi

Colours:
- Space Grey
- Gold
- Rose Gold
- Silver
- Chrome
- Yellow Gold (18 Carat)
- Rose Gold (18 Carat)

New Features:
- Digital Crown
- watchOS