Marineland's Visi-Therm Deluxe Heater is reliable and accurate. It maintains a temperature within one degree of the set temperature. The temperature is easy to set and it lets you know with a "click" sound for every adjustment. The Visi-Therm Deluxe also lets you know when it is working with a clearly visible LED on/off light. Newly designed unit features a double-strength glass casing for extra protection against aggressive aquarium dwellers. Newly designed mounting bracket features three windows for easy visibility of temperature setting.
I have a 4 gallon acrylic tank with filter and hood for my Betta. I needed a heater I could depend on keeping this tank at a temp. between 78-80 degrees and short enough to submerge in the tank. The Visi - Therm Deluxe really does a nice job. ever since I put this heater in the tank it has kept exact Temp that it is set at. My Betta thanks you Visi - Therm.