Littelfuse ZA Series Varistors The Littelfuse ZA Series Varistors are radial lead transient voltage surge suppressors (MOVs) designed for use in the protection of low and medium-voltage circuits and systems. Typical applications include motor control, telecom, automotive systems, solenoid, and power supply circuits to protect circuit board components and maintain data integrity. Available in model sizes 5mm, 7mm, 10mm, 14mm, and 20mm, the Littelfuse ZA Series Varistors feature a wide VDC voltage range of 5.5V to 615V.