Hi guys. Im new to glamisdunes.com, and new to ATVs and the sand as well.
Question is I hear my friends talk about powerbands on their quads, but I don't know what one is. Can someone explain? Thanks =)

All engines have a powerband, it's not something you add to them.
It's where your engine makes the most of it's power. Some are "bottom-end" power so you can maximize low rpms, some are "mid-range" and some are "top-end", and some have a powerband that extends throughout the whole range of the engines available rpm. Stock Banshees are usually top-end; taking off at full throttle it will feel like there isn't much power at all and then as the rpms rise it gains more until you feel a "hit" in the upper rpms and it'll try to rip your arms off.

Exactly what washroad said. The powerband isn't a part, rather it is the RPM range or "band" that the engine performs at it's peak.

Two strokes generally have a narrow powerband making most of their power in the mid to high revs (Not always true) where four strokes have more of a linear powerband as in they make gradually more power the faster the engine spins. This is not always the rule but usually applies.

You will and should notice the powerband on your banshee as your accelerating. You have hit powerband once your arms have ripped off trying to hang on from the yamahas crazy power.

As the above said. A powerband really 'hits' you on a 2 stoke, as the horsepower comes on in a burst. The best analogy I can give is to say it's like a turbo spooling up. A 4 stroke's powerband is smoother, you feel power as soon as you hit the throttle and it picks up from there, like a normally aspirated car engine.

Just go buy one

here ya go...

Where can I get one of those powerband quads? I heard they are real fast?