These are the officially licensed Hogwarts house uniform Snuggie-like wearable throw blankets available from Fun.com. They come in one size, adult standard (48" x 71"), and cost a very reasonable $20. Oh man -- I'm going to buy one for my girlfriend, then record her opening it on Christmas. "To my favorite Hufflepuff -- WTF is this?! You know I'm a Ravenclaw!" Sorry honey *donning the Ravenclaw throw I bought myself* but I saw you take that quiz online.
Thanks to Angela, who agrees the best witches and wizards are warm and comfortable witches and wizards.