In Win loves to use glass elements with their cases, and the 503 is probably the most affordable unit out there with one. The front panel, which may be pushed down to reveal a 5.25" drive bay is made out of glass and is protected by a thin layer of plastic right out of the box.
The 503's design is once again excellent, just as we have come to expect from In Win. Clean lines, great attention to detail, and a perfect mixture of colors make the chassis look snazzy. The PSU bay on the bottom of the rear, the layout is quite traditional.
The chassis features a large side window that is extruded slightly to give you more space within. A large silk-screened In Win logo has been placed on the window as well. Turn the In Win 503 over and you will see a similarly shaped side panel without a window, which creates some symmetry while giving you more space to nicely route cable behind the motherboard tray.
You may slide the front glass panel down with a gentle push, which reveals the 5.25" drive bay. This is a truly nifty way of making the design beautiful, but functional. You will find the I/O facing forward right above the glass plate. It consists of a USB 3.0 and two USB 2.0 plugs and the usual audio I/O. While a good mix, two USB 3.0 plugs would have been nice. Most boards only feature a single 20-pin header while offering multiple USB 2.0 plugs. With the 503, you will have to use the full USB 3.0 header to power a single plug.
The PSU bay in the rear can hold a unit with the fan facing up- or down as there are two sets of mounting holes, the seven expansion slots are only accessible externally, and those six covers on the bottom are of the break-out kind, which makes closing off any holes should your system configuration change impossible. Only the very top cover is reusable since it is held in place by a screw. All the way in the top is a red LED-equipped 120 mm fan set to push hot air out the back. It unfortunately comes with a Molex connector and will, as such, run at full throttle all the time, making it rather noisy when it does not have to be.