spare bulb exspense lol
go to local salvage yard and raid some headlamp bulbs for a dollar or two
we suffer low temps here in the uk a lot of my racing in the winter is done in the -4 to 5 deg celcius range and this will be a god send to ease of starting and give my engine a longer life i used to use a headlamp bulb off a stick pack but now purpose built heater on its way
would have to be 12v as power limited here at uk tracks were all grass roots racing normally in middle of nowhere and dont have the support that usa tracks seem to have
one day when i win on lotto i wanna come out and sample the us style dirt tracks cant wait