Physical description

.1) Specialist wooden slide rule for use with range setting of Vickers Machine Gun. Brown varnish with black print on both sides. Two wooden slides pull out from top or bottom. There is a two foot cord at top.
.2) Brown corrugated leather case for above. The flap is secured with a steel knob.

Inscriptions & markings

Both sides: “MG MK III WHH 1940 (.303 Vickers MG for MK VII Ammn” [Ammunition])