Abstract: A circuit protection device is formed from a resistive element composed of a PTC conductive polymer composition and two electrodes. The conductive polymer composition contains ethylene/vinyl acetate copolymer having a vinyl acetate component of less than 30% by weight of the copolymer, and a melting point of at most 105° C. Devices of the invention have a resistive element thickness of 0.025 to 0.25 mm; a crosslinking level equivalent to 1 to 20 Mrads; a surface area of at most 120 mm2; a resistance at 20° C., R20, of at most 0.050 ohm; and a PTC anomaly from 20° C. to (Tm+5° C.) of at least 103.5. The devices can be used as part of an assembly in which the device is in contact with a battery, e.g. a rechargeable battery.