The set is sometimes incorrectly referred to as the 'Number II', which is incorrect; the British Army used Arabic numerals to designate radios, and the 'number two' was a larger, small-run unit for divisonal communications.
The unit had an operational voice range of 15 miles, although the Long Range Desert Group used the radio to transmit Morse in excess of 1,500 miles (a feat which was only possible at certain times of the day).