Physical description

US Magnetic Compass:
Made in 1966; used in Vietnam War
(Sometimes referred to as a Surveyor's Compass or, less accurately, a prismatic compass).
When unfolded, the user puts a thumb through the wire loop, holds the lens in front of the eye, and aims the wire 'aiming line' at the required object or direction. While held, the user then looks down towards the dial to read the compass direction.
The engraving underneath includes a reference to radioactive material ('H3' – the tritium isotope of Hydrogen) and is used in the luminous paintings that mark principal compass directions.

Inscriptions & markings

(with lid closed)
U.S.
COMPASS MAGNETIC
FSN 6605-846 7618
UNION INSTRUMENT CORP.
PLAINFIELD, N.J.
DA23-195-AMC-00906(T)
(lid open; distance scale on edge - see Media item #5)
1000 2000 3000
1:25000 METERS
(underside)
RADIOISOTOPE H3
A.E.C. LICENSE NO. 8-5736-3
CONTAIN 75 MS. RADIOACTIVE H3
DO NOT OPEN
DISPOSE OF PER AR 755-380
IF FOUND RETURN TO
MILITARY AUTHORITY