Bowl-Clear plastic, contained in a black plastic outer casing having a rectangular aperture through which card is viewed. Inside of bowl fitted with a white plastic lubber line. Corrector magnets are fitted above and below bowl. Mounted in a black painted bulkhead mounting bracket.
Card-Dia:1.5" (3.8cm). Black plastic with white markings on vertical edge, graduated to 360 degs.
Needle- Two needles of square section mounted below card.
Pivot-Stem mounted to base of bowl carries a brass (?) pivot which engages in jewelled cup moulded into centre of plastic card.