Bowl-White translucent material, with a patent bubble trap at base. Fitted to a black painted brass verge ring. Inside of bowl painted white with four black lubber lines marked on side. Mounted in gimbal ring 6.5" (16.5cm) dia. which acts in one direction only and which is attached to outer casing by four linked rings. Outer casing brass 7" (17.8cm) dia. fitted with flat cover which has a glass viewing window mounted in a raised cone.
Card-Dia. 4" (10.2cm) Grey painted mica (?) of floatless type, with black markings graduated to 360 degs. Attached by four wire struts to pivot at centre. Above pivot are four curved metal struts which curve upwards towards verge glass, to prevent card lifting off pivot.
Needle-Two needles of circular section 2" (5.1cm) long, mounted below card.
Pivot-Jewelled pivot cap carried at centre of card engages on pivot stem secured at base of bowl.