Fly Reels - Anti Reverse by Henschel®

This allows a fish to pullline off of the reel whenever a fish fulls the line with a force greater than the drag setting.
As line is pulled off the reel, the retrieving handle does not spin with the spool.

Advantage:
Whenever a fish pulls the line with a force greater than the drag setting, he will pull line off of the reel protecting from break-offs. When you are fishing for large fish, a spinning handle on the reel can be dangerous to the fisherman.

Disadvantage:

You can not override the drag setting when landing a fish.