Key benefits Maintains stable water temperature for a range of habitats, helping protect fish, reptiles, and water features from temperature stress. Clear overheating protection with proactive alerts to prevent damage or stress to inhabitants. Simple, precise control with an external controller that keeps hands dry during setup and avoids extra accessories. What it does Overheating protection: If water temperature rises above 36 C, the display shows HH and the indicator light turns yellow. Normal operation resumes automatically when the temperature drops below 34 C. Broad compatibility: Suitable for fighting fish tanks, mini tanks, turtle tanks, horned frog tanks, pet drinking fountains, and similar setups. Intelligent and precise constant temperature: USB heating rod with a settable temperature range from 15 to 34 C. When the water temperature is 0.1 C below the set point, the unit enters a temperature control state to maintain stability. External controller: Includes an external temperature controller. Easy to install and operate. Specifications and features Heating method: USB powered heating rod Temperature range: 15 to 34 C Overheat alert: Display shows HH with yellow indicator light when above 36 C Reset threshold: Normal operation resumes when temperature falls below 34 C Controller: External temperature controller for easy operation Compatibility: Works with fighting fish tanks, mini tanks, turtle tanks, horned frog tanks, and pet drinking fountains Use scenarios Betta fish in a small desktop tank: Maintain a comfortable water temperature to reduce stress and support healthy activity. Turtle tank or horned frog habitat: Provide reliable warmth in compact enclosures where consistent temperatures are important for health and feeding behavior. Pet drinking fountain or small water feature: Keep water at a stable temperature to support hydration and reduce microbial growth. Notes The system emphasizes safety with clear overheating alerts and automatic resumption of normal operation once temperatures stabilize. Designed for easy installation and operation with an external controller, requiring minimal maintenance.