Safe Rugged construction – Built in shatterproof QUARTZ tube wrapped with two heating element mica plate and nickel wire along with high-impact plastic housing hygger submersible Aquarium Heater ensures the safety of your pets while maintaining proper temperature At-A-glance Temperature Display -- heater rod shows real time water temperature and indicator light It will be red when heating green light when the proper temperature has been reached External Knob controller Memory Function -- allows you quick set temperature without getting hands wet especially in winter adjustable wide temperature range of 59AF to 93AF in 1-degree increments Memories last setting when you unplug it to water change Out of Water Shut Off Protection -- feature to ensure it doesnAt overheat and cause harm to your livestock Turn off before it exceeds desired temperature Shatterproof plastic guard protects fishturtle from impact and making contact easy to detach to cleaning great For Small Shallow Tank -- slim flat profile mini tank heater measures 43x 18x 09 which is quiet space saving and easy to hide behind filterwoodrock with two strong suction cups mount Thanks to the flat design it can be placed vertically or horizontally at gravel free aquarium bottom to heat up low water level turtle tank