Blue marbled Penol Ambassador no. 5 fountain pen

Blue marbled Penol Ambassador no. 5 fountain pen. Push button filler. A new rubber sack must be inserted before it can absorb ink and write again. All parts are original to this model. No damage or repairs. However, the “button” on the small black short bottom screw is missing, which is why there is a hole - see photos. Length 13 cm