This is the Velleman board mounted inside a Maplin Project box (Maplin being the main UK high-street stockist of the Velleman 8055) but any enclosure will do as long as it is big enough to accommodate the board (which is 145mm x 90mm) with about a centimetre extra or so each way for a bit of clearance. Note the spacers on the 6BA bolts (not sure what the M-size equivalent is) of which there are 4 more on the underside; these help to make things a bit less fiddly during assembly. Along the top are the rear ends of 5 phono sockets wired to the input terminals on the left of the board. Each of the 5 inputs has an on-board push-button (labelled Inp1 to Inp5) which is useful for confirming that the board is working if your external wiring is a bit dodgy (or without the external buttons connected). The terminal block on the right is for the output ports of which there are 8, each with its corresponding tell-tale LED. This is not needed for our purposes although I am considering adding an oversize 7-segment display to show the player number of the person who pressed to supplement the pop-up on-screen window in the program.
If you fancy yourself as a bit of a whiz with a soldering iron, it is possible to save yourself a tenner by buying the board in kit form but, having once assembled a ZX81 from a kit, I decided that there is a distinct lack of fun involved as far as I am concerned and bought mine ready-assembled. The square silver box to the right of the printed copyright notice is a USB-B socket that takes the same kind of connector as you find on most USB printer leads (not supplied with the board). You also need to be a bit nifty with a drill and file, as holes will need to be made in the plastic case for the 4 bolts, the 5 phono sockets and access to the aforementioned USB-B socket.