This adaptor is used to extend the distance of a microphone with an 8-pin telephone style connector to the base radio unit. The extension lead LE001 (Female to Female) can also be purchased as a separate accessory. The LE001 and the AD001, along with a black housing is also available as part number AD008, which is included in the box for all remote base radios (eg. TX3340/3540/TX3345/TX3620UB, TX3820UB series radios).