It's quite clear that the Define R4 is an updated version of the R3 as the aesthetics of the two cases are very similar indeed. Both feature the same minimalistic design, consisting of a large brushed aluminium style door in the front of the case, covering all of the drive bays and fans.
Behind the door there are two 5.25″ bays at the top which are secured in place using clips. They also feature vents which provide airflow to the inside of the case.
The inside of the door is covered in foam which should help to keep noise levels to a minimum. There is room for two 140 mm fans in the front of the case which feature dust filters. There is only one fan included in the front with the case but you can easily add another one.
The main chassis of the case is constructed from SECC steel which is powder coated black. The steel used is quite thick and feels very good quality indeed.
All of the front panel connections are located along the top edge of the case at the front. From left to right we find headphone and microphone jacks, a reset button, a power button, two USB3.0 ports and two USB2.0 ports.
There are two additional fan vents in the roof of the case which support 120 mm or 140 mm fans. These are blanked off with noise suppressing foam which can easily be removed if you want to install fans here. Unfortunately the fan mounting holes aren't in the right position for mounting a Corsair H100.
Moving round to the rear of the case we can see that there is a 140 mm exhaust fan included with the case. There are seven expansion slots in total which feature white vented covers which contrast with the black finish of the case.