4GB ( 1x 4GB Module ) DDR3 1066 MHz ( PC3-8500 ) DDR3 SODIMM ( 204-Pin ) Non-ECC SODIMM ( Unbuffered SO-DIMM ) 1.5V - DDR3 Standard Voltage Compatible Equivalent for IBM-Lenovo 51J0494, 55Y3714, 51J0493, 55Y3708, 41R0636 High performance Memory RAM upgrade designed for Laptop/Notebook/All-in-One Computer Systems All modules undergo quality assurance testing to ensure dependable and reliable performance Please verify the supported memory (RAM) specifications of your system prior to purchase to ensure compatibility A-Tech provides a Lifetime Warranty for all orders & offers complimentary United States based Tech Support before, during, & after your purchase