Apparently the keychain not only can put your keys together. If you also need a handy portable charger, the solar power bank keychain may be a nice solution.
This is a practical and easy-to-use portable charger with keychain that measures 2.3 x 5 x 2.3 inches. As shown in the images, the power bank sports an ultra compact design, and using included keychain, you can easily attach it on your backpack or organize your keys. Moreover, the portable charger comes with built-in rechargeable battery, and integrated 30-pin and Lightning ports let you conveniently extend the battery life of your iPhone 4/4S or iPhone 5/5s/5c. In addition to a USB port, the portable charger also features an integrated solar panel for an eco-friendly way to recharge the backup battery.
The solar power bank keychain comes in two colors and is priced at $35 USD. If you need it, jump to Urban Outfitters for more details.