LR43 / 186 Alkaline button battery as used in many small consumer products such as toys, small video games, clocks, thermometers, flashlights and remote controls.
Button Cell Batteries are Hazardous (new or used). Keep batteries away from children. These Batteries can cause severe or fatal injuries within 2 hours or less if swallowed or placed inside any part of the body. Medical attention should be sought if it is suspected a battery has been consumed or inserted; Call the 24-hour Poisons Information Centre in Australia on 131126 or New Zealand on 0800 764 766 or contact your country's emergency department.