Note
QST, Oct 1963, p. 179.
QST, Dec 1963, p. 168.
CQ, May 1965, p. 107.
"A" version with tone source and speaker
"B" version without tone source and speaker
"F" version with attached cover, tone source and speaker
Review: QST, Mar 1964, p. 48.
Review: CQ, Apr 1964, p. 48.