RND Dock and 2nd Battery Charger for HTC Thunderbolt 4G Synchronize & Charge your HTC Thunderbolt Phone with the USB cable. Charge an extra battery with the AC adapter. Power Protection Circuit included. The docking holds your smart phone and provides convenient access on your desk or nightstand. RND Power Solutions products comes in professional retail packaging and offers a 1 year hassle free warranty. 100% Customer Satisfaction is our Goal. PLEASE BE CAREFUL when buying products on Amazon and only buy from trusted sellers. Sellers without authorization may sell an inferior quality product carrying no branding. Examples of some trusted sellers would be RND Power Solutions and Amazon. Authentic RND Power Solutions products will have our branding on the product and packaging.