Littelfuse Metal Oxide Varistors - UltraMOV Series Littelfuse UltraMOV series of MOV's are transient surge suppressors that are ideal for applications requiring high peak surge current ratings and high energy absorption capability. The UltraMOV series are primarily intended for use in AC line voltage applications such as TVSS, UPS, AC Power Taps, AC Power Meters or other products that require voltage clamping of high transient surge currents from sources such as lightning, inductive load switching or capacitor bank switching.