2x2GB PC3 DDR3 chips for sale. They work fine and came from a 2009 27" iMac. I just upgraded to add more RAM. Manufacturer is Hynix, information from the chips is: 8500S - 7 - 10 - F2 HMT125S6BFR8C-G7 N0 AA. These can be added to an existing 4GB setup to get you up to 8GB Would also suit regular Windows laptop that uses PC3 DDR3 chips.