Graham it's a common 2 pin automotive connector, usually for 12 volts but if it's a home made set-up it could be either 5 volts or 12 volts. You can get an attaching plug at SuperCheap or Repco or most of the automotive dealers or, cut it off and put something more suitable to your needs/equipment standards. Polarity won't generally matter.
.This could be the part number: ST7021-2.8-21 (or DJ 7021-2.8-21). From memory it's a 2.8mm pin and 21mm length, I honestly can't remember but I know my 92 Falcon uses the same plugs everywhere. No longer used in Automotive as they've gone to fancy waterproof units but still easy to get.
If you have a multimeter you could measure the resistance and work out the heat at 12 volts and at 5 volts based on wattage.
https://calculator.academy/heater-re...ce-calculator/
Probably 12 volts to run with astro related stuff, auto shop for matching plug or simple replacement of something more standard/suitable for your use, the 5mm barrel jack plugs are cheap online if you have a soldering iron handy and the old RCA connectors as used on stereo/video equipment are also suitable and easy to work with (old audio lead).
This CN thread should give you a comparison, I didn't read through it but made my first heater using resistors for a camera lens.
https://www.cloudynights.com/topic/8...er-resistance/
