Black painted white metal circle with black painted brass arms, graduated 0-180 by 30'. With three arms 13.75" (35cm) long; centre arm fixed and two outer arms fitted with verniers both graduayed 0-30 and clamps. In fitted wooden box 19.1 x 10.1 x 3" (48.5 x 25.5 x 7.7cm) containing three extension leg connecting screws and one chart pricker whcih can be inserted through aperture at centre of circle.