You can use up to two Sidekicks on your stroller at one time.
Orbit Baby has US Patent 8714582 on our Sidekick ride along board. When attached to your rear wheel, it resembles a skateboard for your kids' enjoyment, and is able to attach to one side of your stroller, not in the middle or using both wheels, and it stays away from you accidentally kicking it with your feet while strolling. Because of this design and patent, you are able to attach a Sidekick board on both sides of the stroller