Emergency Light Query

[gehl@domain.elided]

Students,
Now that we have covered garage lighting basics, it is time for the 
JoelB school of trouble lighting.  The mention of an old battery 
powering a discarded headlamp has me thinking ... I once saw a 
head plunger with a round small headlamp stuck in it, all wired 
for jumper emergency lighting.  Has anybody ever seen one of 
these ... are am I dreaming?  What do you use for an emergency 
12v field lamp?  How good are the under bonnet Jeep lights as 
previously mentioned? ... good lighting? ... durable?
Mark