|Note_en=stands for '40s second half, at least from 1948 ([[aerometric]] started to appears that year). Advertising for the [[Parker 51]] model, citing the [[Advertised Feature::aerometric]] system. Mention the [[Quink]] ink and the ''[[Advertised Feature::Solv-X]]''. | |Note_en=stands for '40s second half, at least from 1948 ([[aerometric]] started to appears that year). Advertising for the [[Parker 51]] model, citing the [[Advertised Feature::aerometric]] system. Mention the [[Quink]] ink and the ''[[Advertised Feature::Solv-X]]''. |