Original
By certification 
Type N Thermocouple (Nicrosil / Nisil)
The Type N shares the same accuracy and temperature limits as the Type K. The type N is slightly more expensive. The type N has better repeatability between 572F to 932F (300C to 500C) compared to the type K.
Type N Temperature Range:
Maximum continuous operating temperature: up to 2,300F (1,260C)
Short term use: 2,336F (1,280C)
Thermocouple grade wire, -454 to 2300F (-270 to 1,260C)
Extension wire, 32 to 392F (0 to 200C)
Type N Accuracy (whichever is greater):
Standard: +/- 2.2C or +/- .75%
Special Limits of Error: +/- 1.1C or 0.4%
Consideration for bare wire type E thermocouple applications:
The type N holds up better to oxidation at high temperatures when compared to the type K.
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