With this purchase, you will be donating a resistance cord to our swim team. These resistance cords help our swimmers increase in strength and speed. They are dual purpose- resistance swimming and assisted swimming. The resistance swimming increase a swimmer's strength while the assisted swimming helps swimmers to feel speedy. This piece of equipment is a practice favorite. We currently have one and it is getting old. We would love to have one for every lane (6). Thank you for donating this item to our team.