Need a good voltmeter

[lincpimp]

Was wondering if anyone knew of a decent voltmeter. I need it to be small enough to be mounted on the vehicle (old emaxx) and capable of reading up to 25v. And cheap too. It would be nice if it was backlit, but that is not a requirement. Not sure what one of these run on, seperate battery or thru a receiver port? I do not have an lvc on the bk9920 and it does not matter much, but it would be nice to see the pack voltage at a glance without taking the body off.