This tiny amplifier is a VERY close copy of the Marshall MS-2, cosmetically, and electronically. The circuit is almost identical, using a LA4140 power amp IC driving a 8 Ohm 3 inch speaker. Three identically functioning knobs and a rear mounted pocket clip. Construction is very much in line with the price, rigid injection molded plastic. Sound is pretty one dimensional, lo-fi and distorted and not much more. The Power knob is a three position switch, Off, On, and OD, presumably for "Overdrive". The On position is somewhat clean-ish at best. The OD position is pretty distorted. The amp is fairly quiet overall, even inOD mode with the volume cranked. Loud enough to annoy a roommate, but that's about all. The On setting I find not very useful. Better to just use OD, crank the Volume control all the way up, and use the guitar's volume control to control the amount of distortion-simple and effective. The Tone knob isn't all that useful. Despite the published rating of 5 Watts, this amp is nowhere near that. Maybe 0.5 Watts at most, fully distorted. Versatile this amp is not. It does one thing. And it does it cheaply. That's what you pay for, and that's what you'll get. Whether that one thing is useful is entirely up to you. If you're in the market for the Marshall MS-2, buy this one instead. If you're looking for a tiny bit more versatility and clean sounds to drive a small loudspeaker, you'll have to look elsewhere and probably have to pay significantly more.