TEMP-FLEX-35 Low Temp Extension Cord. Temp-Flex-35 was developed to meet the demands of contractors for a super flexible vinyl cord set. Specially formulated SJTW vinyl outer jacket won't crack or break, even at temperatures as low as -35° F. Highly visible yellow color for safety. Low Temperature Extension Cord Set. Flexible Round Yellow Cord, 300V, SJTW, UL Approved 50 ft. 10/3 Yellow.