Quantity of 1 unit equals 2 feet of cable. Here you can add extra cable length in increments of 2 feet to the Male S7-10 connector which comes 8 foot long , or to the Female S7-08 which standard length is 4 feet. Please specify in the additional notes area to which cable(s) you wish to add the length. Please note that most Airstream trailers require 10' of cable to get to the junction box which would be 1 unit.