https://losangeles.craigslist.org/lac/sys/d/macbook-pro-retina-15-inch/6450805952.html Serial  Number C02NKHT4G3QC Display Retina display: 15.4-inch (diagonal) LED-backlit display with IPS technology; 2880-by-1800 resolution at 220 pixels per inch with support for millions of colors Native resolution: 2880 by 1800 pixels (Retina); scaled resolutions: 1920 by 1200, 1680 by 1050, 1280 by 800, and 1024 by 640 pixels Processor 2.2GHz 2.2GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.4GHz) with 6MB shared L3 cache Configurable to 2.5GHz quad-core Intel Core i7 (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache or 2.8GHz quad-core Intel Core i7 (Turbo Boost up to 4.0GHz) with 6MB shared L3 cache. 2.5GHz 2.5GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache Configurable to 2.8GHz quad-core Intel Core i7 (Turbo Boost up to 4.0GHz) with 6MB shared L3 cache. Memory 16GB of 1600MHz DDR3L onboard memor