My pet sitter told me about this cool little disc. It looks like a frisbee. After you heat it in your microwave for 6 minutes, it emits heat of 120 degrees Farenheit for 12 hours. I use it to keep a homeless kitty that has adopted me warm at night. I just heat the disc, stick it in a box under some blankets on my porch, and the kitty is ecstatic. He sits on it like it's an egg, purring. It's safe and very effective on cold winter nights. This is a really great gift for anyone who loves cats.