Don't let a dead battery ruin your productivity; always have replacements on hand. Batteries not only power important gadgets like remote controls and wireless mice, they also power very important essentials like flashlights and smoke detectors. Checking these items regularly is vital, and so is making sure replacements are available if a battery is expiring. OfficeSupply.com stocks batteries of all sizes. Find AAA batteries, AA batteries, calculator and watch batteries, along with rechargeable batteries and batteries specially designed for electronics such as cameras.