No hearing aid battery lasts longer than Rayovac Size 312 Hearing Aid Batteries based on ANSI performance tests. Engineered with a balanced formula, the cells in each mercury-free size 312 battery provide consistent, high-quality performance for power-hungry hearing aid devices. Use these batteries in your listening devices and hearing aids for reliable hearing assistance. Convenient packaging includes a reclosable front door that presses down and snaps closed easily to protect the remaining batteries, and the secure dial on the back stops the package from spinning, giving you complete control over each hearing device battery.