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NOTE: iMac Mid 2010 27 inch iMac 11,3 (3.2 GHz) and 21.5 inch iMac 11,2 (3.06 GHz/ 3.2 GHz/ 3.6 GHz) ONLY SUPPORT 4GB, DO NOT SUPPORT 8GB.
Compatible for Apple MacBook Pro -13 inch / 15 inch / 17 inch Early 2011, 13 inch / 15 inch / 17 inch Late 2011 – MacBookPro8,1 MacBookPro8,2 MacBookPro8,3

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Design For Apple Late 2015 iMac 27-inch w/Retina 5K model ID: iMac 17,1 (i5 3.2GHz, i5 3.3GHz, i7 4.0GHz)
JEDEC standard 1.35V (1.28V ~ 1.45V) and 1.5V (1.425V ~ 1.575V)

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Design For Apple 2017 iMac 27-inch w/Retina 5K Display model ID: iMac 18,3 (i5 3.4GHz, i5 3.5GHz, i5 3.8GHz, i7 4.2GHz)
Design For all Apple 2017 iMac 21.5-inch w/Retina 4K Display or Non-Retina Display model ID: iMac 18,2 (i5 3.0GHz, i5 3.4GHz, i7 3.6GHz) and iMac 18,1 (i5 2.3GHz)

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DDR3L 1600MHz PC3L-12800 204-Pin Unbuffered Non ECC 1.35V CL11 Dual Rank 2Rx8 based 512×8 Module Size: 8GB Package: 4x8GB
Designed for Apple iMac – 21.5 inch / 27 inch Mid 2011, 27 inch Late 2012, 27 inch Late 2013, 27 inch Late 2014, 27 inch Mid 2015- iMac12,1 iMac12,2 iMac13,2 iMac14,2 iMac15,1

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DDR3 1066MHz PC3-8500 204-Pin Unbuffered Non ECC 1.5V CL7 Dual Rank 2Rx8 based 256×8 Module Size: 4GB Package: 1x4GB Guaranteed – Lifetime warranty from Purchase Date Free technical support
Designed for Apple MacBook – 13 inch Late 2008, 13 inch Late 2009, 13 inch Mid 2010 – MacBook5,1 MacBook6,1 MacBook7,1