Montblanc Vintage 244G Fountain Pen
24Xs are not super uncommon. They were not as expensive as the 1XX line, not the as economical as the 3XX lines. It fills via Piston Filler and has a BB nib, which is not super common and it has the matching BB marking on the blind cap.
The pen is also in great condition. No major issues, imprints are nice, no major brassing.