A 28.35g 1oz. reel of 28swg Constantan 55-60 copper 45-40 nickel wire suitable for making rheostats etc. Can be used as a thermocouple when twisted with copper wire. A temperature difference between the wires of approx 25 C gives around 1m V with temperatures in the range 0 C to 50 C. Resistance 4.2 Omega per metre.