Submersible Aquarium Heater Explosion-Proof Auto Thermostat Fish Tank Heater with Protective Sleeve & Suction Cup, Digital Temperature Readout, 300W / 100W FULLY SUBMERSIBLE: IP68 Double impermeable sealed technology prevents electricity leakage,Plastic protective sleeve is scald-preventing for your pets and safe operation for you, The Strong suction cup clamps TIGHTLY FIX the heater to the tank easily TANK CAPACITY: Our heater is suitable for 10 to 30 gallons aquariums, suitable for most tropical freshwater and marine aquariums.As the outputed temperature from heater is not equal to the whole water temperature of tank,PLEASE SETTING THE TEMPERATURE BASED ON THERMOMETER EXPLOSION PROOF: 1.5 mm extra thick Quartz Glass is shatterproof, shatter resistant & more durable than conventional glass heaters ACCURATE THERMAL CONTROL: Maintains the temperatures from 68F to 94F (20C - 34C). the suitable temperature for most fish is 76 to 80F (25- 27C).The inner temperature controller on the top adjust the desired temperature, comes with an thermometer to show the accurate tank temperature to avoid overheat or freeze(If the thermometer is lost in delivery, contact us we will solve it) Voltage/freq: 110-120volt/60hertz, We recommend to position it near a strong water flow, the outlet of a power filter is ideal, so that the whole aquarium are in the same temperature. AttentionDO NOT power on until the heater is completely submerged in the water.Please don't put it in the water if the wire or glass tube damaged