Bowl: Grey painted brass, filler plug at side and four side expansion chambers fitted. Bottom of bowl glazed, for illumination and projection of card. Inside of bowl painted white and fitted with black wire lubber point projecting from side of bowl. Mounted in grey painted brass gimbal ring.
Card: Diameter 3.25" (8.2 cm) Mica card, outer edge unpainted with black markings, inner part black with white and black markings, graduated to 16 points and quadrantally in degrees. Attached to white painted float at centre which carries a jewelled pivot cap.
Needle: Two magnets of circular section mounted below float.
Pivot: Has brass stem in which jewelled pivot point is fitted, attached to bridge fitted to base of bowl.
O.A. height 2.75" (7.0 cm)