When your family grows, your stroller can too. The Thule Sleek 2 Sibling Seat converts your Sleek 2 stroller into a double without giving up a thing. The sibling seat has the same recline options, magnetic buckle and adjustable footrest as the main seat, so both riders are equally comfortable. It also works alongside a car seat, bassinet or rider board, giving you the flexibility to configure around whatever stage your kids are in.