For sale four(4) 4GB chips of PC4-2666MHz DDR4 of SK/ HYNIX RAM, totaling 16GB RAM. I purchased the green ones two months ago and the black ones came in my newer iMac a month earlier. I am not an expert on memory so I doubt I can tell you anything that I haven't listed. When I looked for memory for my iMac this brand wasn't suggested by Google however since my machine came with two of these in it I figured it would be best to match up. Hope this finds someone's iMac or laptop to help.