Got this on a super sale deal, glad I didn't pay any more for it.  My 6 year old wanted a new toy gun.  Knowing what he does to them figured I'd go cheap.
It takes 2 AA batteries, which I didn't know about - makes a laser type sound when you put them in.  Not obvious that it takes them so for a younger child, you could probably get away with not putting batteries in.
It's not extremely loud, but can be extremely annoying.