|Note_en=Advertising for the [[Parker 51]] model. Describing the [[Aero-metric Ink System|Aero-metric]] system and the ''[[Pli-glass]]'' reservoir. Mention also the ''[[Lustraloy]]'' cap. | |Note_en=Advertising for the [[Parker 51]] model. Describing the [[Aero-metric Ink System|Aero-metric]] system and the ''[[Pli-glass]]'' reservoir. Mention also the ''[[Lustraloy]]'' cap. |