The enclosure in the packet gave me a synopsis of what it is.
It is believed that each woven web will catch your dreams in the night. The bad spirit dreams will get caught in the web and disappear with the morning sun. However, the good spirit dreams will find their way to the center spirit hole and will float down the sacred feather.
The Legend of the Dream Catcher
A spider was quietly spinning his web in his own space. It was beside the sleeping space of Nokomia, the grandmother. Each day, Nokomia watched the spider at work, quietly spinning away. One day as she was watching him, her grandson came in. "Nokomia-iya!" he shouted, glancing at the spider. He stomped over to the spider, picked up a shoe and went to hit it. "Nokeegwa," the old lady whispered, "don't hurt him." "Nokomia, why do you protect the spider?" asked the little boy. The old lady smiled, but did not answer. When the boy left the spider went to the old woman and thanked her for saving his life. He said to her, "For many days you have watched me spin and weave my web. You have admired my work. In return for saving my life, I will give you a gift." He smiled his special spider smile and moved away, spinning as he went. Soon the moon glistened on a magical silvery web moving gently in the window. "See how I spin?" He said, "See and learn, for each web will snare bad dreams. Only good dreams will go through the small hole. This is my gift for you. Use it so that only good dreams will be remembered. The bad dreams will become hopelessly entangled in the web."