Hi. I fitted one of these a year ago, and so far it has worked well for 10,000 miles. Transmitters fit inside the wheel rim, whilst the receiver runs off the bike electrics. A couple of shots taken at slightly different times. I like seeing what my tyre pressures are before heading off. Display updates within about 30 seconds from switching on the ignition. I am told the transmitters should last for about three years before replacement is required.