"A means of getting more sound draining your pocket."2.5 starson by DeprMo
Pros: A pre amp for home stereo, motorcycle sound, or garage sound: provides treble & bass boost: drive small speakers directly: It's a cheap way to get get a little boost or a little sound where you need it.
Cons: Unit can get very (scary) warm. Sound is every bit what you should expect for $20. As your turn up the volume, bass, & treble, unwanted noise increases in kind.
Summary: Good choice for an affordable if not disposable means of addressing low power issues on many types of primitive sound applications. You get what you pay for.