This Asahi Pentax Marine 7x50 with a 7.3º view is a rugged build binocular, water proof and has fine optical performance. The image is bright and crisp with great central resolution.
These "Marine" designated models are superior to the other models in the Pentax range, using high index prisms and better lenses. See attached folder.
It was produced by JB 2 = The Katsuma Kogaku Kikai Co.Ltd.