This is the smallest incubator heater. You can use it in other devices too, where you need to low heat. This can be power up by 12v DC. I heat up at starting my incubator within 6 minitues, then it keeps the tempareture steady by the temperature controller. So should use temperature controller. Temperature controller I used,https://www.amazon.in/Robocraze-W1209-50-100-Temperature-Controller-Thermostat/dp/B072KT75D3

My incubator size is (16X10X6) inches. It takes 6 minutes at stating heating up 30'C to 38'C(without eggs).

You can drive this heater by car battery or PC UPS battery if mains line gone.

I used 12v exhaust fan. Dimensions 40mmX20mmX40mm. Similar exhaust fan I used in the heater,https://www.westfloridacomponents.com/J647APK08/12V+.10A+5+Blade+DC+Brushless+Fan+40mm+Delta+DFB0412H.html

I used a coil to heating up the device. You can find the zip in the attachment to making details of the coil. You have to make it yourself.

Thanks,Mahbub