Cylindrical body with brass end fittings. There is no
cats whisker, instead an adjustable arm alters the movement of one mineral
against another. Marketed as the alternative to glass enclosed cats
whisker detectors and "the discovery of 1925".
The first advert I have found for this detector is in
the June 1925 edition of The Wireless Constructor magazine (page 787).
A later advert taken from the Popular Wireless and Wireless Review magazine
dated Oct 2nd 1926 (back cover) is shown on the right - click the thumbnail
to enlarge. The instruction leaflet that came with the box is shown
below.
