Smiths Aircraft Instruments “Waymouth” fuel contents gauge test set, dielectric type. A specialised aircraft ground-maintenance instrument used to test and calibrate fuel quantity indicators that operated with capacitive tank probes. The unit simulates electrical and capacitance conditions so engineers could verify correct gauge operation during servicing. Housed in a fitted wooden transport case with instruction plate inside the lid. Aviation maintenance equipment, mid-20th century, c.1950s–1960s.
