HBM-1 (24 cm)
Scale ruler, outside edges respectively read to 30 Nautical Miles in 1:250,000 and to 6 Nautical Miles in 1:50,000. Centre scale reads to 11 Kilometres in 1:50,000 scale and to 60 Nautical Miles in 1:500,000 scale.
Scale ruler, outside edges respectively read to 30 Nautical Miles in 1:250,000 and to 6 Nautical Miles in 1:50,000. Centre scale reads to 11 Kilometres in 1:50,000 scale and to 60 Nautical Miles in 1:500,000 scale.