BRITISH MILITARY WRIST / THIGH COMPASS

British military compass on long, canves strap for wear on the arm or the thigh. 1.5 inch diametere casing with flip up lid with mirrored inner surface.. Rear of case marked No15742/B. Khaki webbing strap with brass buckle. Total length of strap is 23 inches, allowing this to be worn on the thigh when seated. This suggests use by Seaborne units such as the SBS. I understand this to be post WW2 period Very clean, grade 9