Product Specs: Technology: DDR3 SO-DIMM Density: 4GB (4096MB) RoHS: Yes Comp Count: 16 Depth: 256Mb Width: x64 Pin Count: 204-pin Op. Temp.: 0C to +85C Data Rate: DDR3-1333 Speed: PC3-10600 CL: CAS 9-9-9-24 Cycle Time: 1.875ns Voltage: 1.5V Comp Config: 256Mb x 8 ECC: Non ECC Module Ranks: Dual Rank Register: Non Parity. Low Noise 8-Layer PCB Meets and/or Exceeds Specifications. Fully Compliant with JEDEC specification. RoHS Certified Warranty Safe Upgrade. OWC Memory Lifetime Limited Warranty including the OWC Lifetime Advanced Replacement Program. Compatible with: iMac: 27-inch Mid 2011 (May, 2011) Model ID: iMac12,2 (2.7GHz i5, 3.1GHz i5, 3.4GHz i7);iMac: 27-inch Mid 2010 (July, 2010) Model ID: iMac11,3 (2.8GHz, 2.93GHz, 3.2GHz, 3.6GHz);iMac: 21.5-inch Late 2011 (August, 2011) Model ID: iMac12,1 (3.1GHz i3);iMac: 21.5-inch Mid 2011 (May, 2011) Model ID: iMac12,1 (2.5GHz i5, 2.7GHz i5, 2.8GHz i7);iMac: 21.5-inch Mid 2010 (July, 2010) Model ID: iMac11,2 (3.06GHz, 3.2GHz, 3.6GHz);Mac mini: Mid 2011 (July, 2011) Model ID: Macmini5,1 & Macmini5,2 (2.3GHz, 2.5GHz, 2.7GHz); Mac mini: Mid 2011 Server (July, 2011) Model ID: Macmini5,3 (2.0GHz); MacBook Pro: 17-inch 2011 (October, 2011) Model ID: MacBookPro8,3 (2.4GHz, 2.5GHz); MacBook Pro: 17-inch Early 2011 (February, 2011) Model ID: MacBookPro8,3 (2.2GHz, 2.3GHz); MacBook Pro (15-inch 2011)(October, 2011)Model ID: MacBookPro8,2 (2.2GHz, 2.4GHz, 2.5GHz); MacBook Pro: 15-inch Early 2011 (February, 2011) Model ID: MacBookPro8,2 (2.0GHz, 2.2GHz, 2.3GHz); MacBook Pro: 13-inch 2011 (October, 2011) Model ID: MacBookPro8,1 (2.4GHz, 2.8GHz); MacBook Pro: 13-inch Early 2011 (February, 2011) Model ID: MacBookPro8,1 (2.3GHz, 2.7GHz); PC Laptops: Compatible with PCs capable with the specifications listed above. Memory complies with JEDEC Specifications, document JESD79-3B.