Increase the performance of your computer with the reliable Crucial CT4G3S1067M 4GB DDR3 1066 Unbuffered RAM, compatible with your Mac system. RAM Features Type: 204-Pin DDR3 SDRAM Form Factor: SO-DIMM Capacity: 4 GB Speed: DDR3 1066 Voltage: 1.5V ECC: Non-ECC Dimensions: 66mm x 30mm Compatibility: Mac