Note
QST, Jul 1959, p. 154. (Johnson ad)
QST, Jan 1968, p. 160. (Harrison ad)
QST, Apr 1974, p. 122. (keys now being sold by WIlliam Nye Company)
Probably much earlier than this. Several variations including:
114-301 – basic key (note: listed by Harrison as 114-310)
114-311-3 – with switch (from Harrison ad)
114-311 – chrome base (from Harrison ad)
114-320 – heavy duty, black base (from Harrison ad)
114-321 – heavy duty, chrome base (from Harrison ad)
114-100 – high speed (from Harrison ad)
114-100-3 – high speed, chrome base (from Harrison ad)