  The amperage is on the label of the ballast. When you connect the ballast to power you will see it along with the voltage and pf of the ballast. F40T12 twin 8 foot tubes, ballast usually draws about .75 amps. The amperage is on the label of the ballast. When you connect the ballast to power you will see it along with the voltage and pf of the ballast. F40T12 twin 8 foot tubes, ballast usually draws about .75 amps.
A Single Din is the standard size of a head unit (the stereo in the dash of your car) a double din is twice as large. Double dins are good for cars that have large stock head units like a caddyhas.
Many double din units will use the same audio processors and DACs that the single din units of the same brand do, so they often have the same sound quality. Often the advantage of going single DIN is that they are generally cheaper because they don't have the added bells and whistles of touch screens, etc. This means you can spend less money ($200-300) for a unit that has the exact same audio quality as a double din unit that costs $700+.