Uses phase lock loop (PLL) technology providing a more stable frequency than other standard expanders Ensure the best reception from your car radio. (This is not an antenna booster) Shielded from external RF interference. 12Volt DC operation. Negative earth only. Will increase FM band up by 20MHz (Does not change AM Signal) Tune radio to 81.1MHz to receive 101.1MHzInstallation as you watch. Call 0722 100506/0751100506