I have one and I use it for bigheads.

The battery is just a 9volt so you can't keep the button pushed for very long or you'll drain it out. By just pushing it for a few seconds at time (sweeping the water in front of the boat looking for bigheads) I can get mine to last for at least four hours. It's a suprising bright light.

If you kept it pressed down straight, I doubt it would last for 20-30 minutes.

SO... It's great for bigheads. (much handier than a hand held spotlight)

I have also used it for commons, and had good luck with it for that too. However, if you're walking along the shore, you'll want some sort of flashlight or caplight to see where you're going. Otherwise, you might use up the battery too quickly. It also will not penetrate very far into the water. That's to be expected from a light it's size.

I just use it without the lens cover. Robow tried the red lens and didn't find it particularly helpful.

Another thing..... Get the good duracell batteries for it. Also, if you get the battery really wet, it swells up real neat like. [:-]

I bought them in bulk for the club last year and we got a really good price for our members. If there's enough interest I can do that again. Just let me know.