With interchangeable, twist-and-lock covers, Skip Hop's multipurpose stackable snack containers are perfect to use as a formula storage container and lots more, whether used separately or stacked together. Featuring indented sides for an easier grip, the seven-piece transparent container set lets you easily view what's inside. Use as a formula container with the easy-pour formula lid for feeding baby on the spot. Or fill with munchies for family trips. Just pack, stack & snack!