Heath Outdoor Products SC-51 Sunflower Stack'ms Seed Cake 6.4-ounce, case of 6 each. Made in Canada, our Stack'ms seed cakes are specially blended to help you attract several types of birds to the same feeder. Mix and match flavors to find the perfect combination for your yard. Simply stack Stack's on your Stack's feeder, where they will be easily accessible to birds but sheltered from the elements. Guaranteed fresh.