The Mattlures Hammer tail bluegills feature a patent protected tail design. The Hammer tail gets its name from the thump you can feel as you retrieve it through the water. Because you can feel the tail thumping, you will have confidence the bait is doing what its designed to do. If you can feel it thumping then you know the bass can to! This tail will swim at any reasonable speed. From ultraslow to about as fast as you can reel. Because of the tail design the baits can be made with a harder, stronger plastic and still perform exactly as they are supposed to. With the use of this stronger plastic these baits are very durable. The baits sit at rest with their nose down and their tails slightly upward. When they sink, they swim downward instead of spiraling. They come in 2 sizes: Ultimate Hammer Tail: 5 1/2" length – 2.15 oz. U2 Hammer Tail: 4 1/2" length – 1.30 oz.