Marina Aqua-Minder is designed to provide each aquarium with both cosntant temperature monitoring and a schedule for regular maintenance. The Aqua-Minder flashes and beeps when programmed maintenance is due and/or when the temperature has fallen below or risen above the programmed levels. Marina Aqua-Minder Thermometer & Maintenance System+ digital thermometer and date display+ audible alarm when temperature exceeds/falls below ideal range+ visually highlighted schedule for regular water changes, filter maintenance and the system check+ size: 8.3 x 9.4 x 1.6 cm+ display of temperature inC orF+ fatsening with velcro stripe Marina Aqua-Minder is designed to provide each aquarium with both cosntant temperature monitoring and a schedule for regular maintenance. The Aqua-Minder flashes and beeps when programmed maintenance is due and/or when the temperature has fallen below or risen above the programmed levels. The health of your fish depends on accurate water temperature and good water