2 electrical questions

[burton907 0]

so i've seen videos and people have a little digital volt reader on there dash, it reads how many volts the battery (or alt?) is putting out, and it has blue numbers... where can i find one online and what are they called exactly.

also, i can't exactly afford 1/0 gauge power wire set from street wires, which is who i want. and i can't wait any longer to get my system put in my new car. i have a SAE 1000D amp with a 12" Fi Q going into a 2001 grand cherokee. stock alt is 100amps. anyways, i used the 4 gauge in my previous car, even though it's rated for 600w, thats what people on here told me to use. i wanna upgrade my system to a BTL or Xcon, i haven't decided yet, but i want to upgrade my amp too either an SAZ 1500 or 2000. i know the 4 gauge will hold me back quiet a bit with the upgraded system when i get it, but is it worth paying 200 dollars ontop of the 120ish that i'd pay now for the 4 gauge. i plan on upgrading as soon as possible, probably within 6 months.

[johnecon2001 82]

Most people use the Stinger Volt Meter. It comes in blue or red.

As far as wiring goes, 4awg is good up to 150A or around 1500w. While headroom is nice, 4awg will be fine for your application.