Quality material: The drawstring of sack is made of satin cord which is non-stretch, durable and sturdy, the sack is made of polyester, not easy to break, can be applied for a lasting time Easy to use: Fill the sack with food by the funnels. Next, tighten the sack with the drawstring. Finally, tie the bag to a tree. Several simply steps will offer wild bird enough food. Easy to wash: Can be washed by both hand and washing machine. Just empty the sacks and wash them with water or throw them in your washing machine. it will be clean enough for you ti reuse. Nice Holes: Hole size is suitable, Quality mesh won't fall apart after a couple of fillings, cord lock keeps seed from spilling out even if sock is dropped Applications: the fine and soft mesh design makes this sock bird feeder good for for goldfinches and other small birds to eat from this product