Bowl-Bowl consists of a glazed expansion chamber. Painted white inside and outside grey. Bowl rotates in its holder and can be easily removed. On inside of bowl is a lubber rib which has a sensitised strip along length. It is set in gimbals.
Card-White domed float card with 10 degree section cut out. This section is set 5 degrees either side of rib.
There is a graduated ring on compass platform graduated 0-360 by degrees. There is a corresponding scale graduated W15-0-15E next to ring. There is an overhead arch on top of which is a cup for carrying corrector magnets. Set in own carrying box complete with wires, leads and a light.