With a new improved design, this automatic aquarium heater is for both fresh and saltwater aquariums. Unit has a precision bi-stable thermostat with plus or minus 1/2 degree F holding temperature. The temperature setting is an easy to adjust control dial with accurate 1" increments from 65 to 93 degrees. Ebo Jager have a 2mm thick thermal shock resistant glass vs the common 1mm thickness for and extra sturdy construction. Heater also includes a 6 foot double insulated power cord, and a convenient clip-on heater holder.