1. The controller regulates the speed of standard 4-pin Intel PWM fans only; it does not turn fans off. It features full digital control, precise temperature setting, and accurate speed regulation. It supports both manual speed adjustment and automatic temperature-based speed control. Manual speed range: 10%–100%, adjustable in 5% increments. Automatic temperature control starts at 30°C, with 49 selectable temperature setpoints. 2. Power input: Red and black wires connect to a 12V DC power source. A 3-pin connector with a 2510-3P plug is provided for compatibility with motherboard fan headers that monitor fan speed. A large 4-pin interface allows convenient power connection from the PC case. 3. Temperature probe: The small black probe has a short tip and low thermal mass, enabling fast response and suitability for narrow spaces or ambient air temperature measurement. The ring-type probe is housed in a 4.2mm-diameter metal ring, designed for secure mounting—e.g., on radiators or other heat-emitting surfaces—using screws. 4. Manual/Automatic mode integration: Manual mode operates without the temperature probe. Press or double-press the up/down buttons to adjust speed steps. Each step remains active for 20 seconds before auto-saving. During this period, LED #2 flashes rapidly (indicating temperature control is inactive). Flashing stops once settings are saved. LEDs #3 and #1 remain steadily lit when minimum or maximum speed limits are reached. 5. With the temperature probe installed, manual speed sets the base (minimum) fan speed. When ambient temperature exceeds the configured start temperature, fan speed increases smoothly as temperature rises. At the configured full-speed temperature (start temperature + temperature range), the fan reaches maximum speed and maintains it.