This Lenovo 51J0494 compatible 4GB DDR3-1333MHz Dual Rank Unbuffered 1.5V 204-pin CL9 SODIMM is 100% guaranteed to be compatible with your system and to work right the first time. Adding additional memory is the best way to increase the performance of your system. All our memory is built to strict JEDEC standards to meet or exceed the Tier 1 OEM's factory requirements. Our products are also guaranteed by federal law to not affect or void OEM warranties.

• 4 GB of memory to refine your computer's performance
• 204-pin-pin DDR3 SDRAM interface synchronizes electrical and clock signals for an efficient data transfer rate
• Up to 1333 MHz speed with Unbuffered signal for playing the latest games and using heavy software