R.E.L. means Research Enterprises Limited and was founded by the Canadian Government on July 1940. From 5 June 1941 optical glass came into production in Toronto. Rangefinders, tankperiscopes, radarequipement and binoculars were produced.
50.000 6x30 binoculars and 25.000 7x50 binoculars were procuced. They were tested by dropping them 1.80 meter into a box filled with sand. They were also sprayed with water.
C.G.B. means "Contract Great Britian". GA indicates "with Case"