64GB (4 X 16GB) Kit Memory for Apple iMac Late 2015 27-inch 1867MHz DDR3 SO-DIMM iMac 27-inch with Retina 5K display [Model ID: iMac 17,1] Memory Speed: DDR3 1867MHz (PC3 14900) Memory Type: 204 pin SODIMM Cas latency: 11 - Voltage: 1.35V Rank: Dual Rank Lifetime Warranty