Not all are powered, sizes range from 6-12" woofers, 50-200watts, and come in different colors: black, white, Fake NOS bottle, Fake Scubba bottle; they are simple to install with the built in amp and the 8" fits perfectly behind the seats of a 98+ Reg cab. Prices range from $50+ on ebay. Mine is only a 50 watter but I like it, I dont care about SPL. Mine distorts past a certain point, which usually the point where it becomes too painful to enjoy. I had 2 10" Sonys with a 620 watt amp, and prefer the tube.