Note
QST, Dec 1954, p. 157.
Allied Radio catalog 1960 (copyright 1959), p. 403. (KW-4M)
Universal called this a "CoAx Ratiometer" (complete with the odd capitalization) with the term "s.w.r." in parenthesis (complete with the periods).
The sensing unit of Universal Service’s CoAx Ratiometer installed in the feedline between the transmitter and antenna or tuner. The remote indicator could be placed at the operating position. Its meter read SWR and relative power. The operating range of the Ratiometer was 2–200 MHz at power levels of 10 watts to 1 kilowatt. Separate products were available for 50Ω and 75Ω lines.
The sender unit and the meter could be purchases separately.