This plastic worm is designed with the most hydro-dynamic principles, was tested and prototyped many times to find the proper curve dimensions to get the best swimming style tail. It swims effortlessly and is not just another swim tail worm other than in appearance. You would have to see these designed curves work in rhythm with each other to produce the most efficient fluid movements of this type of tail. This worm will even swim with only the weight of the hook itself!