This is a k-type thermocouple wire with yellow PVC insulation, which is good up to about 105 C or 221 F. This Type K thermocouple wire can be used to make your own thermocouples for a wide range of applications or to make your own extension wire. The chromel alumel wire is made to standard thermocouple specifications. The inner vinyl insulation is color coded according to ANSI Type K, note that red is the (-), and yellow is the (+) wire in k-type thermocouples. It is sold in 10 yard (30 ft) rolls, so if you order 2 units of this, you will receive a 2 rolls, each 10 yard long.