Air Gauge Question

So what's the red light for, sketchy?

so i dont forget my compressor is on. i forgot once and the compressor pushed 500psi before the a/c line blew a fitting.

to bad you couldnt set it up to have a Beeping noise go off inside the cab when its at max psi, kinda like the door when its opened and your keys are still in...that kinda beep, along with the light.

yea thats a really good idea. I was wondering if i could put something like that in but it would prob be easier jsut to put in a pressure switch.