The Blackburn 2'Fer Xl Bike Light - 2 Pack makes it a 4'Fer. This light works hard, pulling double duty as either a 200 lumens front or 40 lumens rear light, depending on your needs. With the push of a button, the 2Fer can switch between a white 60 lumen front light and a red 20 lumen rear light. Holding the button for 2 seconds turns the light on and off, and pushing the button once changes modes between white solid, red solid, white flashing and red flashing. The light also remembers which mode you were last using and turns on in that mode.