Model 357 Bushing Mount Potentiometers Vishay / Spectrol Model 357 Conductive Plastic Bushing Mount Type Potentiometers offer a cost-effective solution with the compact size and advanced design technology. The potentiometers are suitable for all industrial applications. The Vishay / Spectro Model 357 components come in a 7/8' (22.2mm) diameter single turn size and feature a resistance range of 1kΩ to 50kΩ.