I've done a lot of research on rechargeable batteries and these are the best of the best. Sanyo use to make them which is how I knew about the Eneloop batteries. I probably have 20 of them laying around my house. They hold a charge for a very long time. Even if you charge them today, they don't go flat in a month like an Energizer rechargeable batteries. When I saw this kit at Best Buy for $20 on clearance, it was a no brainier. Now made by Panasonic they still retain the same Sanyo technology that made these batteries famous. I used them in everything from my Nikon SB-700 flash unit to my keyboard and mouse that I use daily. I'm surprise that I haven't recharge the one in my flash unit yet. I don't use it often either and they still work 5 months down the road. I highly recommend that you grab this if you see it on the rack.