Card- Mica covered with paper. White with black and white markings, graduated to 1/4 and 1" from edge is a circle of degree graduations with two rows of figures 0-9 quadrantally and 0-360 (for use with Gilberts azimuth circle). Card is perforated by 8 holes, for an unknown purpose.
Needle- Two edge bar type of laminated clock spring steel 7.5" length x 0.5" deep and 1.75" apart. A brass crossbar is fitted at each end to secure needles to card. A brass cross frame, attached to needles, is fitted at centre to carry pivot.
Pivot- Cone-shaped brass pivot cap with jewel at top screwed through centre of cross frame.