Listed batteries I've used for this MS wireless 3500 so far. Conditions: *mouse uses one AA *usage = 6-8 hrs/day, everyday *choices were down to what's available at grocery stores close to our house *all are alkaline # Eveready {black and red} - terrible {lasts less than 1 week} # Eveready Gold - bad {lasts 3-4 weeks} # Energizer Advanced - inconsistent {lasts between 1 week and 3 months} Using Energizer Max now {cheaper than Energizer Advanced so I guess Max will have a shorter life on the MS 3500} but had no choice, the store doesn't have anything else. The mouse originally came with a Duracell - that one lasted 6 months. Need to get a Duracell but will have to get that at a hardware store at the town plaza.