An accurately balanced magnetic needle, strongly magnetised is fitted with hardened steel pivot marking in jewels cup bearings. The needle can be easily removed for reversal. The inclination scale is of chrome brass graduated in degrees 0-90 four times. The case is made of non-magnetic steel alloy, duco painted, has easily removable plate glass window and rotates fully on a heavy brass base, is rotation being measured by a brass chrome dial reading 0-360o. It is fitted with levelling screw and spirit level.