I found them here...

http://www.jannsnetcraft.com/circle-...ks/820519.aspx

As to why... I have limited experience with them; but had some last summer and consistently caught the bluegill and redear in the corner of the mouth with them using piece of worm under a bobber. I was really surprised at how well they worked. Not sure if fluke or common; but decided worth trying more seriously this spring.