Navy Type 98 Reflector Gunsight . Very similar to Revi in design. Has front mount suitable for installation in fighter aircraft. Knob at rear is a rheostat for "Dark" and "Bright." 255mm l, 210mm h; Has reflector glass & alternate ring & post.
Dimensions
Retained in natural finish box: 11-1/4"x 13"x 6". 255mm long, 210mm high