I bought two sets of two batteries from this seller and I couldn't be more pleased with the price and the quality of them! I have only used them a couple of times, but all four batteries charged up nicely (with the $5 charger also on Overstock!) and they lasted all day at the wedding I was shooting. Mind you I was using my camera for 8+ hours continuously, and the batteries never hinted at being close to dying or low on battery. They took about 3-4 hours a piece to charge fully, but they have been kicking ever since. Since they are off-brand, I decided to get four batteries instead of just two (since my d90 takes 2 at a time). However, at this price, it is affordable to get two sets and have a back up, and it's still lower than the price of buying one set of the maunfacturer made batteries. I would highly reccommend these to people that are looking to get back up, or main batteries for their camera!
