DC STANDARD RESISTOR 9409 has been designed and fabricated to meet the standard calibration requirements. These Standard Resistors can be used for calibration. To ensure stringent accuracy, high degree of stability and utmost reliability, the Manganin wire and strips have been used to construct Standard resistors. These Standards incorporates the manganin coils which have been subjected to prolonged ageing and heat treatment, to improve stability and to reduce temperature coefficient. Joints are silver soldered with copper being used for connection to terminals. Resistance elements are sealed in aluminium container having moisture free oil. Use of oil improves cooling effect which in turn imparts greater stability to resistance.