A Closer Look - Outside
It looks like the Tranquil PC NUC chassis is cut out of a solid piece of aluminum and is, according to the company, then hand-polished before it is anodized. The chassis is quite heavy and strays a bit from the traditional 4x4 inch size. It is a bit wider but not much deeper to ensure there is enough material to cool all interior components properly without requiring a fan, unlike the Intel case itself. A panel on the underside of the Tranquil NUC protects the interior and all to-be-installed components. Four little feet, part of this block of aluminum, are also part of the overall design.
You will not find any LEDs or buttons in the front. There is only a single hole for the Intel 3rd generation i3-based NUC's default USB 2.0 I/O. Both sides are identical, but this particular angle nicely shows what Tranquil PC has done to passive cool everything: The chassis is essentially shaped like a big heatsink that wraps around the board.
You have all the default openings for the D33217GKE board in the rear. These consists of two USB 2.0, two HDMI, and a Gigabit network plug with its power lead; on the left is another opening for a WiFi SMA connector. This gives you the ability to retain any wireless connectivity as long as you can get your hands on a little adapter and antenna. A larger, circular hole on the right is for the power button/LED combo.