Apple iMac A1418 21.5" (Late-2013) i7-4770S 3.1GHz, 16GB RAM, 1TB HDD

Specs at a Glance:

• 21.5" 1920x1080 LED-backlit 16:9 widescreen IPS display
• Intel Core i7-4770s 3.1GHz quad-core "Haswell" processor
• 16GB DDR3 RAM
• 1TB Hard Drive
• NVIDIA GeForce GT 750M (1GB GDDDR5)
• FaceTime HD Camera
• Four USB 3, two Thunderbolt, Gigabit Ethernet and SDXC card slot
• Wi-Fi 802.11ac and Bluetooth 4.0
• macOS 10.13 High Sierra
• Apple Wireless Keyboard and Magic Mouse

More spec details below, courtesy of our friends at EveryMac.

The iMac "Core i7" 3.1 21.5-Inch Aluminum (Late 2013/Haswell) features a 22 nm "Haswell" Quad Core 3.1 GHz Intel "Core i7" (4770S) processor with four independent processor cores on a single chip, a 6 MB shared level 3 cache, 16 GB of 1600 MHz DDR3 SDRAM, a 1 TB hard drive, and a NVIDIA GeForce GT 750M graphics processor with 1 GB of dedicated GDDR5 memory. It also has a built-in "FaceTime HD" webcam and stereo speakers, but lacks an optical drive.

This model has a 21.5" 1920x1080 LED-backlit 16:9 widescreen IPS display with the "cover glass fully laminated to the LCD and anti-reflective coating." The rear of the case is aluminum and is thicker in the middle and tapers to a razor thin 5 mm at the edges.

Connectivity includes four USB 3.0 ports, dual Thunderbolt ports, Gigabit Ethernet, 802.11ac Wi-Fi (802.11a/b/g/n compatible), and Bluetooth 4.0.

Compared to its predecessor, this model essentially has the same external enclosure, but it has a much more efficient "Fourth Generation" processor and architecture, as well as faster graphics, faster Wi-Fi, and the option of faster storage.