Marathon's dual timer is able to simultaneously record two (2) separate activities with a functional duration of up to 99 hours, 59 minutes, 59 seconds. Timer features an alarm volume setting switch to allow for use in noisy areas with the 'hi' setting, quiet environments with the 'lo' setting, or 'mute' setting when only the visual flashing indicator is desired. This is the perfect timer for hearing impaired, noisy areas, schools, cooking, or other activities. Includes 2 AAA batteries.