I came up with this cozy idea a few weeks ago when the cold weather really started to set in. I love the idea of portable heat sources that use little energy and allow me to roam freely around my cold house (I generally keep the thermostat at 60 degrees all winter.) The owl cable came from an old Leisure Arts vest pattern I was given a few years ago. This cozy will dress up any standard 2 liter hot water bottle and it will keep it warmer longer.