Best Deal from Amazon.com : https://www.amazon.com/gp/product/B00OH6TFSG?tag=chriskressera-20
8GB RAM Memory Upgrade for Lenovo ThinkPad Edge E431 62775KU by Arch Memory
Product Description :
Arch Memory is a Registered Trademark of Arch Computer LLC
Bus Type PC-12800
Data Transfer Rate 1600Mhz
Pins 204 Pin
System Type Laptops