Card- Mica covered with paper. White with black markings, graduated to 1/2 points with a decorated East point, graduated quadrantally in degrees. At centre of card is a 2" hole to accommodate pivot mounting. One balancing stud at S by W point.
Needle- Four light edge bar needles 2 x 6", 2 x 3" mounted on a light metal rim.
Pivot- Inverted type, carried in a double gimbal which is attached to card by two knee pieces of metal.