Interior diameter:0.81 inch Minimum rated working voltage:DC4.5 5V-24V Maximum current:15 mA(DC 5V) Working voltage range:DC 5-18 V Load capacity:10 mA(DC 5V) Operating Temp:80°C,Operating humidity:35%-90%RH Allow compression:Water pressure 1.20 Mpa below Storage Temperature:-25-+80°C Storage humidity:25%-95%RH F=4.8 * units of flow(L/min)* time(seconds). About the Wiring: Red Connect Positive; Yellow OUT Connect signal output; Black GND Connect Negative. SUitable for water purifier,,credit card machines,water vending machines, coffee machines,smart card equipment,the boiler and and other flow measurement devices! Caution: Prohibite dramatic impact and chemical erosion. Prohibite throw or hit. Vertical installation,inclination is no more than 5 degrees. Media temperature should not exceed 120 degree. Colour:Black material:plastic Package Contents: 2* Water Flow Sensor Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Impeller inlaid stainless steel beads,always wearable. Model Number:FS400A :Plumbing Flow range:1-60L/min Note:The color of the item slightly due to photography and your own computer