SOT Leads or ISO T-Harness adaptors allow aftermarket products like parrot bluetooth kits, satellite navigation units, handsfree car kits, amplifiers, tracking systems, bluetooth devices etc. that are supplied with standard ISO blocks to be installed into vehicles with quadlock connectors. Male to Female conversions allows aftermarket bluetooth car kits to be plug directly into the car radio speaker wiring without making any modifications. SOT (Sound on Top) lead allows connection of a hands free kit with standard ISO wiring, such as a Parrot kit without damaging the radio's original wiring. The lead allows audio muting and hands free phone calls to be heard through your vehicle's front speakers and also provides power to the hands free kit.