Littelfuse Polyswitch Resettable Fuses - Raychem RXEF030, The Littelfuse Polyswitch is a resettable device that performs like a fuse under overcurrent conditions, but is unique in that it will reset.
As soon as an overcurrent condition is reached the Polyswitch heats up to its trip temperature.
Littlefuse RXEF030 0.
3A Polyswitch Fuse