This pen knife has a Carbon steel blade with a German Steel branded on it. There is No. 57 branded on the blade, which might be the model number. There is also a two flower brand. The scales seem to be good quality white early generation plastic maybe celluloid. The blade length is 6 cm and total length with blade open is 13 cm. With the blade closed it is 7 cm in length. It weighs about 35 grams.
It is optimized for both left and right handed use. Both sides are absolutely flat ground.There is hole for a lanyard.
This knife is a slip joint knife meant for art/craft work or to take as a EDC (every day carry). It can be used to sharpen knives, cut strings and so on.