Canon
BG-E2N
Battery Grip for EOS 30D, 40D & 50D
Compatible with up to two BP-511, 511A, 512, 514 Lithium-ion battery packs or six AA batteries with BGM-E2 battery holder (included). Provides additional shutter release, main dial, AE lock/FE lock and AF point selection controls to assist vertical shooting, as well as 1/4-20 Size tripod mount thread. Water and dirt resistant for excellent durability and to match the water resistant capability of the EOS 40D camera.