I have the one bought off ebay from digtronics. This is wired into my stero unit, and can have either internal senders or scew cap ones. Beauty of this is that you dont need to have another screen attached in the car. My in dash unit has DVD, Stereo FM, AM, CD 6 stacker internal, MP3 plug external, Apple external Plug, Reverse Camera, and IGO 8 and Oziexplorer. Can handle any number of tyres. You just select which 4 you want to monitor at any one time.