Saving energy and battery life is the main goal on the Cateye Hybrid HL-EL020 Handlebar Light. How does the Cateye Hybrid light sustain this? It stores solar energy in the rechargeable battery, but no need to worry about running out of solar power, because the Cateye Hybrid holds a AA battery just in case you need a backup plan. You can utilize both light sources up to 36 hours, and you can choose if you want to use solar or the battery. On top of the handlebar light you will see a blue light when your using solar power, and a orange light if you are using the battery. Retail price is $60.