Mac os high sierra. Version 10.11.6 . Macbook Pro (11.-inches Mid 2011). Processor is 1.60ghz Intel core i5 With 128 GB SSD Drive . With 4cpus with 4 cores . Memory is 4 Gig 1333mhz . DDR3. Graphics Intel HD Graphics 4000 1536 mb . Serial number .C1ML1496DTY3. 500 HDD Drive . Keyboard light . Bluetooth. Card reader . webcam . HDMI . etc . Mac os High Sierra . Excellent Battery Life .