The JD Gear Bug Hat Light is an ultralight, super-bright, white LED light that attaches to the bill of your hat and provides enough light to help you tie your flies on in the dark. Total weight is less than 1/3 of an ounce with batteries. The two Lithium Coin Cell batteries it uses are included. Burn time is 12 to 14 hours of continuous burn time. Total length is approximately 2 inches. Clip this little guy onto the bill of your hat for those early mornings or last evening hatches.