Increase the resistance of your Stamina AeroPilates reformer with a simple cord switch. Use the two included cords to replace the existing black cords in your Pilates reformer to increase the force of resistance by 40%. Installation is quick and easy with the included instructions. This is an excellent way to add new challenges to your regular Pilates workout. * Set of 2 Pilates reformer resistance cords * For use with any Stamina AeroPilates reformer * Increases resistance level by 40% * Elastic cords with nylon cover and plastic knobs * Quick installation- just replace existing black cords * Includes installation instructions * Manufacturer"s warranty included (see product guarantee)