Designed for use with the phil & teds Vibe Single Stroller, the "doubles kit" attaches to the back to convert the stroller from a single to a double. No need to buy a whole new double stroller, click in the kit and you are ready to grow - and go! Use the double kit for your toddler up front when you have a newborn, or for your younger child behind with the older child in the main seat. This item is just the doubles kit, stroller is sold separately.