The Solarbulb?This unique way to illuminate your water bottle uses a solar powered cap that screws right on your water bottle's top.Said to fit on most plastic water bottles and soft drink bottles this fun design is able to capture solar power efficiently.
The Solarbulb's adjustable head design allows its user to point the mini solar panel towards the sun.By just capturing 3 to 4 hours of direct sunlight gives you 5 hours of full LED lighting,a great for camping and hiking accessory.
Source:
http://www.lightpublic.com/lighting-products/solar-water-bottle-cap-illuminate-your-water-for-5-hours/
