This tool was probably manufactured sometime between 1956 and 1972.
This is a low angle adjustable mouth block plane. The bedding andle is 13.5 degrees, the blade is beveled to 25 degrees.
This is my go to block plane. The blade requires a small hammer to tap it into the proper angle. It is fairly light, making it easy to hold with one hand. I use it on end grain, and frequently use it to cut chamfers.