Vello BG-C2 Battery Grip for Canon 5D Mark II
At about $60, the Vello BG-C2 battery grip for the Canon 5D Mark II enhances the Canon 5D Mark II in several useful ways, battery life only one of them. Read more.
What I like the most is that it turns the small-body 5D Mark II into a big-body camera, which means I can nestle it into my shoulder for rock-solid pictures at low shutter speeds, what I call “mass coupling”, see How To Hold a Camera Steady in Making Sharp Images for details.