For 25-50 Gal Tanks: Measure 11.4 inches in length. Applicable for aquaculture and fresh, marine and tropical aquariums. Save your fish or plants from coldness to keep them vigorous..Adjustable: Controllable temperature range from 68 °F to 93 °F (20-34 °C). Simply rotate the knob to freely regulate the temperature with deviations from ± 2 °F to ± 4 °F..Detect Temp Timely: With a built-in thermostat, it will automatically keep the water at the set temperature. The extra thermometer sticker allows you to detect water temp at any time..Heating Protection: Its indicator light turns red during working and automatically shuts off to stop heating when reaching the set temperature. No danger of overheating to your aquatics..Reliable Material: The 2 mm extra thick shatterproof quartz glass can prevent electricity leakage. And the iron-chromium heating wires feature fast heating to warm your tank fitly.