Full Details from Amazon.com : http://www.amazon.com/gp/product/B00PKZGE14?tag=onigi-20
4GB Dual Rank Non-ECC RAM Memory Upgrade for HP TouchSmart 520-1050 by Arch Memory
Arch Memory is a Registered Trademark of Arch Computer LLC
Bus Type PC-12800
Data Transfer Rate 1600Mhz
Pins 204 Pin
SODIMM
