The iMac "Core i7" 3.6 21.5-Inch Aluminum (Retina 4K, Mid-2017/Kaby Lake) with four independent processor "cores" on a single chip, a 6 MB shared level 3 cache, 16GB of 2400 MHz DDR4 SDRAM and a 512GB Solid State Drive, and a Radeon Pro 555 graphics processor with 2 GB of dedicated VRAM. It also has a built-in "FaceTime HD" webcam and stereo speakers. 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.