32GB Total. four 8GB PC3-10600S 204 pin SODIMM DDR3 1333MHz Genuine CMS brand, CMS is one of the most trusted names in the Computer Memory industry and this product carries a Lifetime Warranty from
CMS MAX MEMORY: 32GB SOCKETS 4
COMPATIBLE WITH: Apple iMac "Core i5" 2.5 21.5 -Inch (Mid-2011) Mid-2011 - MC309LL/A - iMac12, 1 - A1311 - 2428