Stopwatch The battery is an alkaline button battery LR44. I used it for work, so there are scratches, wear, and fraying of the string. There are traces of sticker removal on the back. AI text below: Waterproof stopwatch with 1/1000 second accuracy, convenient with memory function. - Model: Stopwatch - Waterproof: Water resistant - Accuracy: 1/1000 second - Memory function: With memory function Thank you for viewing.