Canon BP511A 1390mAh Lithium Ion Battery Pack for Select Digital Cameras and Camcorders

Works just fine, allows a decent number of shots. I bought an extra battery to go with my BG2 grip and 40D. With two batteries you can shoot for quite a while.

Yeah I know Canon batteries cost more , but you get what you pay for. Sure you can get the same battery from a different company for as low as $5 on Amazon , but I wouldn't trust those batteries in my equipment. I used to think the generic batteries were just as good until I bought a few. Years later my canon batteries still work and the generics are both almost completely dead. Buy canon batteries for your canon equipment

I have not used this yet but its basically a rule you should always follow. Never buy cheap third party batteries. They usually do not last as long as OEM.

Any serious photography should carry an extra battery with them just in case.

I must admit, I ordered an imitation "equivalent" but even before it arrived, I ordered the Canon model. I had to ask myself "Do I trust my $1,000 camera to a $20 knock-off battery?" The battery life is good, and I'm amazed how fast it charges. Much better than my AA Energizer rechargables.

This is an extra battery that I ordered with my Canon 40D camera. It works well.