ECC REGISTERED UPGRADE: This type of memory is used in Workstations and Servers. It will NOT be compatible with standard desktop computers. Also, it cannot be mixed with UNBUFFERED memory. OWC 8GB UPGRADE: Consists of a single 8GB DDR3L 1600 PC3L-12800 CL11 1Rx4 240-pin 1.35V ECC Registered DIMM Memory RAM Module Upgrade compatible with Lenovo Flex System Compute Node models x220, x222, x240 And x440. INDUSTRY LEADING: Consumer-friendly Advanced Replacement Program and Limited Lifetime Warranty, which includes Free Tech Support by Other World Computing. MAXIMIZE YOUR SERVER: With OWC's ECC Registered Server Memory, you will extend the life of your old infrastructure or save money when building a new one. Replacement for Lenovo part numbers 00D5035, 00D5036, 46W0700, 46W0771, 00D5035, 00D5036, 46W0700 and 46W0771.