[4] Poor working conditions, low pay and long hours, prompted Vos to form the first women's trade union with other dressmakers in 1897, All One (Dutch: Allen Een).

[3] Vos was elected as president of the new organization and wrote articles under the pseudonym "Erve" for their journal, Seamstress's Messenger (Dutch: De Naaistersbode).

[3] At the conference, feminists and socialists of the newly formed Social Democratic Workers' Party (SDAP) clashed on whether class struggle was more important than equality for all.

Vos expressed that the characterization of women workers by socialists failed to address the reality that they must earn a living and that classes could work together to improve conditions.

[1][3] In 1903, Vos took part on the national Defense Committee during the strike[1] and then married a non-Jewish teacher, who she had met in the socialist movement, Melle Gerbens Stel.

[9] In 1909, Stel-Vos left the SDAP and joined the newly formed Social-Democratic Party (SDP) and by 1918, ran for a seat on the Provincial Council of Groningen.

In 2004, a children's book by Els Launspach [nl], Verboden vriendschap (Forbidden friendship), about Vos' involvement in the seamstress union, was published.