The aim is to correcting the compass disturbances caused by iron from the structure of the vessel
At both sides, there are correcting spheres (traditionally painted in green and red)
Inside, there are adjustable correcting magnets on racks
On the back side, there is a vertical soft iron bar placed in a tube called Flinders bar
On the front there is a clinometer used to give the list of the ship
The compass is mounted in a gimbal which keep the compass horizontal.