The toe warmer is a fine secret weapon, it will last for hours. For most folks, booties over summer shoes just don't work at temperatures much below freezing. When removed from the packaging, the air activated warmers come to life for instant heat! When placed inside the secret sock pocket, they will generate soothing heat for up to 6 hours+ Ideal for use when fishing, hunting, skiing, or sitting around the camp fire. Sold as pairs.