What about a guitar amplifier? I play guitar and have friends who do as well. If I'm driving around, would one of my friends be able to plug their amp in and play their guitar?

 

You can buy invertors (and guitar amplifiers) about as big as you want. Just make sure the wattage of the invertor is larger (X 1.2) than the guitar amplifier. If it is really big, you'd better keep the engine running or keep the jumper cables handy.

 

Remember, the power output drops to 300W when the vehicle is in drive.