Card- Mica with painted markings. Black with white markings graduated to 1/4 points and quadrantally in degrees. Has a silver metal circumference graduated to 20' of arc. The quadrantal graduations are inverted to be read through a prism. Card is attached to framework by 10 screws.
Needle- Two edge bar needles, 6.75" (17.2cm) long and 0.5" (1.6cm) wide, are attached to framework. Framework has two sliding brass weights for balancing.
Pivot- Cone-shaped brass pivot cap at centre.