Genuine ADATA 4GB DDR3 SODIMM memory module, specifically the model AO1L16BC4R1-BQ75 or Clos.  Variant . The DDR3L - low voltage DDR3 with 4GB Capacity. It's single rank ( 1Rx8 ) module, meaning it uses chips arranged in one bank for efficient performance in basic task.  Speed PC3L - 12800S, which equates to 1600 MHz (DDR3-1600) This is a standard speed for mid - 2000 to early 2010s laptops. Voltage 1.35V low voltage) making it energy-efficient and compatable with laptops that support DDR3L.