Apple iMac A1418 21.5" (4K Late-2015) 3.3GHz Core i7 8GB RAM 1TB HDD

Specs at a Glance:

• 21.5" 4K 4096x2304 LED-backlit 16:9 widescreen IPS DCI-P3 "Retina 4K" display
• Intel Core i5 3.1GHz quad-core "Broadwell" processor
• 8GB DDR3 RAM
• 1TB Hard Drive
• Intel Iris Pro 6200 Graphics
• FaceTime HD Camera
• Four USB 3, two Thunderbolt 2 (Airplay supported), 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.

This model has a 21.5" 4096x2304 LED-backlit 16:9 widescreen IPS DCI-P3 "Retina 4K" display (that runs "pixel doubled" to look like 2048x1152). 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 3 (USB-C) ports, Gigabit Ethernet, 802.11ac Wi-Fi, and Bluetooth 4.2.

Compared to its predecessor, this model essentially has the same external enclosure, but it has a more advanced processor and architecture as well as dedicated graphics, a brighter display, and Thunderbolt 3 (USB-C) ports.