The Bakelite ring of 6”dia is provided with three windings of 2.50 and 500 turns. Compass box and the ring can both be rotated independently of the base, which is fitted with leveling screws. Compass box is pye type with bakelite case, metal dial, and antiparallex mirror and with aluminium pointer fitted with English jewel.
Same as above but having ringed provided with windings of 2, 5&50 turns. With compass box.