Suffragette, physicist, mathematician and inventor: in the late nineteenth and early twentieth century when few women had access to opportunities in science, technology, engineering and mathematics (STEM), Englishwoman Hertha Marks Ayrton held all these roles and was a strong advocate for social justice, especially suffrage for women. Using material from the Science Museum archives, this paper explores the material culture of Ayrton’s career and work and provides an insight into issues and intersections of gender, science, and technology in the late nineteenth and early twentieth centuries. The article engages with the material culture of Ayrton’s work across multiple fields in STEM. Firstly, it discusses the line-divider, a mathematical tool and engineering drawing instrument Ayrton developed while still an undergraduate at Cambridge and later patented. This was the first of twenty-six patents Ayrton was granted during her lifetime. Next, the paper turns to the electric arc. Ayrton made notable contributions to the understanding of this early and powerful form of electric lighting, and quite literally published the textbook on it. Thirdly, the paper looks at the ‘Ayrton anti-gas fan’, which was distributed in thousands and used to dissipate gas in the trenches on the Western Front during the First World War. Lastly, this paper will explore the impact of gender on Ayrton’s achievements and recognition. Ayrton was elected the first female member of the Institution of Electrical Engineers (IEE), the premier British institution of electrical and electronic engineering, in 1899. However, her nomination as a Fellow of the Royal Society (FRS) in 1902 was declined because of her gender.