This kit has everything that you need to mount a single din radio into the vw mk4 double din radio pocket. To use it you first mount the black plastic pocket from the kit either on the top or the bottom of the opening. I chose the to mount it in the top, to have the radio uncovered by the cup holder at all times. Use the rubber knob off of the factory radio to put on the back of the pocket and support the rear of the pocket, if you look into the opening, you will see holes at the rear of there to insert that rubber knob into. After the pocket is in then you mount the metal sleeve for your radio directly into the opening in the vehicle and slide that radio in. Mounts securely. The wiring harness works good. If you are not aware VW has power on to both of the radio harness wires (red and yellow) at all times and turns it on and off with other wiring that your aftermarket radio will not use, if you want the radio to turn off when you take out the key, you will need to find a wire that turns off with the key removed to supply power to the red wire in your radio harness. For my car this was found on an unused wire in the fuse box, #9 I think, so then when you take the key out the radio turns off. I hope this helps someone out there. If you run your own power wire to the radio, remember to put a fuse inline so that if there is ever a problem, your car does not catch on fire.