Bicycle lights with 2 lights per set. Includes 1 clear headlight with a 20-lumen output, and 1 red tail light with a 4-lumen light output. 2 modes of operation, steady or flashing. 6 to 10 hour run time based on mode of operation. Each light powered by (2)CR2032 batteries, 4 batteries included. Includes O-rings to fit any bar or post. No tools required, easy to install.