OWC 4GB UPGRADE: Consists of a single 4GB DDR3 1066 PC3-8500 CL7 2Rx8 204-pin 1.5V SODIMM Memory RAM Module Upgrade memory module compatible with Lenovo ThinkPad models W500, W700, W700ds, X201, X201i And X201s. 100% COMPLIANT: JEDEC-Standard and ROHS Compliant. Warranty-Safe Upgrade. Designed and Tested to Meet or Exceed all Manufacturer OEM Specs. INCREASED PERFORMANCE: Memory Upgrades are the Most Effective and Easy Way to Boost your PC's Performance. INDUSTRY LEADING: Consumer-friendly Advanced Replacement Program and Limited Lifetime Warranty, which includes Free Tech Support by Other World Computing. EASY INSTALLATION: In Most Cases, Installing Memory is an Easy DIY project. Watch our OWC Basic Installation Video for Help.