Mushkin Enhanced 16GB (2 x 8GB) DDR3 1333 (PC3 10600) Memory for Apple Model 977020A Type: 204-Pin DDR3 SO-DIMM Compatibility: For early 2011 and later Macbook Pros and Mid-2010 and later i5/i7-based 27 iMacs Cas Latency: 9 Timing: 9-9-9-24 Voltage: 1.5V Multi-channel Kit: Dual Channel kit