Features: 1. 100% brand new and high quality 2. The water flow sensor is made of high quality material, long service life. 3. It can install at the water inlet of the water machine to detect the influent flow 4. Small body and stable performance 5. Suitable for water cooler, coffee machine, water filter Specification: Condition: 100% Brand New Model: YF-S401 Monitoring Range: 0.3-6L Accuracy: 3% Wiring Method: Red +, Black -, Yellow For Signal Output (NPN Pulse Signal) Water Pressure Resistance: 0.35MPa Operating Voltage Range: DC5~24V Insulation Resistance: >100MΩ Accuracy: (in 0.15-3L / Min) ±2% Flow Pulse Characteristics: f = (73 * Q)±2% Q = L / Min Output Pulse High Level: >DC 4.7V (input voltage DC 5V) Output Pulse Duty Cycle: 50% ±10% Package List: 1 * Water Flow Sensor