This is an SK Hynix 4GB DDR3L laptop memory module (SODIMM) operating at a speed of 1600 MHz (PC3L-12800S). Key Specifications Capacity: 4 Gigabytes (GB)Type: DDR3L (Low Voltage 1.35V, which is also backward compatible with 1.5V DDR3 slots)Speed/Standard: PC3L-12800S (1600 MHz clock speed)Form Factor: 204-pin SODIMM designed for notebook and laptop computers