This is a Feinwerkbau Model 300 target air rifle chambered in. 177 caliber (4.5 mm), featuring a classic wood stock. The rifle is designed for precision, evidenced by the aperture rear sight and specific stock contouring intended for competitive shooting. Based on the markings, this is a German-made precision air gun, likely manufactured between the 1960s and 1980s. It has the Type 1 sight which was the earlier of the two sights made for this gun.
It also has a hairline crack in the base that holds cap onto the butt of the rifle. Into a gun Im not using, but once done you will have an OEM Feinwerkbau Model 300 in good working order at a discount.