Polaroid Wireless Performance Battery Grip For Canon Eos 50D, 40D, 30D, 20D Digital Slr Cameras - Remote Shutter Release Included Attaches Through Cameras Tripod Mount And Battery Compartment, Durable Rubberized Suface Improves Grip & Handling Intuitive Placement Of Key Camera Controls Makes Portrait Shooting As Easy As Landscape Shooting Provides Up To Double The Shooting Time When Used With BP-511 Batteries Or Equivalent Can Also Be Used With Standard AA Batteries Thanks To Included Speedloader Remote Shutter Release Included, 3 Year Limited Warranty