This electrically insulated 25 gauge nichrome wire can be wound closed or open spaced. Max.temp 594 degreeC. The wire is approx. 1mm in diameter and has a resistivity of 2.1ohms/foot at 20 degree C; maximum ampere rating in open air at 594 degreeC is 3.7amps. The amperes are derated when enclosed and tightly wound; typical for 316 degree C operation is 2.5 amps. Electrical insulation voltage is 1000V The use of a line voltage controller is recommended to properly power the heater element. Packaged in 50 foot lengths.