See reviews @ http://www.amazon.com/gp/product/B001HK4LWA?&tag=mdaydaily-20
Opteka is proud to be allowed to use the same factory and mold as Canon uses for their BG-E5. Opteka is one of the world's leading producers of high-performance batteries and accessories. Opteka believes there is no limit to the potential of portable power, and as a company they will always strive to find innovative and efficient ways to power your life in the future! The Opteka BG-RXS holds 6 AA Batteries or 2 LP-E5 batteries. This provides a extremely extended shooting time. The vertical shutter release also makes shooting with the camera in a vertical position just as comfortable as shooting horizontally. Compatible with the Canon Digital Rebel XS, XSi, and T1i (450D, 500D & 1000D) SLR's only. This package includes 2 LP-E5 Batteries for Maximum shooting time.