RNF & RNMF Series General Purpose Resistors Stackpole Electronics RNF and RNMF Series General Purpose Resistors offer a maximum 2W power rating, 200Vrms to 350Vrms working voltage range, and up to 5% tolerance ratings. These resistors feature precision metal film construction, superior electrical, TCR performances, and flame-retardant coverings. The RNMF series is a mini resistor, making it an ideal choice where size constraints apply. Stackpole Electronics RNF and RNMF Series Resistors have an operating temperature range of -55°C to +155°C.