These flies are perfect imitation of threadfin shad. In our local lakes this is a primary food source for bass. These are designed by striper guru Henry Cohen who fishes down on Lake Lanier. 
They work great on Smith Mountain Lake, Leesville, and Bugg's Island. The hooks are incredibly strong and stupid sharp. Sometimes people say that just to say that - I mean it. I always stick myself when getting these bad boys out of the pack... 
Anyways, the material in the fly allows for it to move and breath much like a real fish. When bass are keyed onto smaller forage that a Clouser can't imitate I tie on of these on. 
This is a great fall & winter striper fly on our local reservoirs.  
These striper flies have a glue coating over the thread wraps to ensure it doesn't unravel. As well, Somethin Else flies are tied with monofilament thread which increases the durability of the fly as well.