The iMac "Core i5" 2.8 21.5-Inch Aluminum (Late 2015/Broadwell) features a 14-nm "Broadwell" Quad Core 2.8 GHz Intel "Core i5" processor (5575R) with four independent processor "cores" on a single chip, a 4 MB shared level 3 cache, 8 GB of onboard 1867 MHz LPDDR3 SDRAM (which could be upgraded to 16 GB at the time of order, but cannot be upgraded after system purchase at all), a 1 TB (5400 RPM) hard drive, and an "integrated" Intel Iris Pro 6200 graphics processor that shares system memory. It also has a built-in "FaceTime HD" webcam and stereo speakers. This model has a 21.5" 1920x1080 LED-backlit 16:9 widescreen IPS display with a fully laminated glass cover and an 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 2 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 more advanced architecture and graphics architecture. The "Late 2015" iMac models shipped with a compact aluminum Apple Magic Keyboard and the choice of either a multi-touch "Magic Mouse 2" or a traditional wired Apple mouse. For an additional US$50, one also could upgrade from the Magic Mouse 2 to the "Magic Trackpad 2," which provides multi-touch and pressure-sensitive "Force Touch" capabilities.