The Quanta FEG 250 operates by using an electron beam to scan a specimen, producing detailed images by analyzing the emitted secondary and backscattered electrons. The environmental capability allows the microscope to be used under low vacuum conditions, making it ideal for observing non-conductive, hydrated, or living samples. The microscope employs a field emission gun (FEG) for a high current density of the electron beam, which improves resolution and image quality.