LED Heel Shoe Clip on Lights, just press a button on the side to toggle from steady red light to flash to off. Each side uses a CR2032 battery (available where ever watch batteries are sold, such as drug stores, WalMart, etc.). You'll need a very small phillips screwdriver, such as used for tightening eye glasses to replace the batteries. Product comes with batteries installed so it will be quite some time before you'll need to replace.  For a product demonstration be sure to check out the video:  Watch Video