iMac 21.5", A1311, EMC 2427. Features a quad core 2.5 GHz Intel i5 processor. 8GB memory, 500GB hard drive and a DVD-RW. Standard are a Facetime HD camera, built in stereo speakers, four USB 2.0 ports, a Firewire "800" port, built-in AirPort Extreme, Gigabit Ethernet, and an SDXC card slot as well as a single "Thunderbolt" port that is backwards compatible with Mini DisplayPort.
Currently running OS 10.12, Sierra, but capable of running from OS 10.6 Snow Leopard to OS 10.13 High Sierra. Comes with a power cable.
Runs great! Screen is scratch free, but there has been some trauma to the aluminum on front bottom edge, and 2 areas on back housing where is surface is rough, as if someone scraped a sticker off.