4SR44 or 4LR44 battery is a small cylindrical battery often used in dog collars, film cameras, small LED flashlights, car security systems, remote controls, toys and similar.

Common labels for this battery are 4SR44 or 4LR44, depending on the exact chemistry, but there are many other labels including PX28A, A544, 28A, K28A, K28L, V34PX, 476A, 4A76, 2CR1/3N, 2CR11108, etc.