Usage Tips:Features: 1.Heavy Duty Sender: All fuel sending units are made of selected reed switches and fixed resistors. SAE 5?hole installation mode, heavy 316 stainless steel, strong structure. Signal output is 240 ohms ? 33 ohms. 2.Application: The fuel level sensor supports Marine, RV, and truck oil level gauges and tank level gauges, with washers and mounting screws to prevent the sensor from touching the bottom of the tank. 3.Installation Suggestion: If the fuel tank is plastic, the length of the gas tank level sensor should be 1in/2.5cm smaller than the depth of the fuel tank, if it is metal, the length of sender should be smaller than the depth 0.5in?1in/1.25?2.5cm. 4.35mm Float: The float is 1.38in (35 mm) in diameter. If a hole must be drilled, a 1?1/2in (38mm) diameter hole would be perfect. The sender has a nonlinear output that can only be matched with a standard meter with a nonlinear signal. 5.Long Durability: The advantage of this doughnut float type level sender over a thick film swing arm type level sender is the durability and reliability of the reed switch. No need to adjust the tank. Specification: Item Type: Fuel Water Level Sensor Material: Body: 316 Stainless Steel Cable: PVC Float: NBR Installation Method: Standard SAE 5 Hole Type Screw Size: M5 x 0.8 Aperture: 5 Mm/0.20 Inch Size: Length 4in(100mm) Recommended Size Of Water Tank:4.35-5in (110-125mm) Output Signal: US Standard 240-33ohms (240ohms At No Load, 33ohms At Full Load) Resolution Range: 10mm Fuel And Water Level Sensor Type: Resistance Rated Current Of Alarm Switch: 500mA Protection Grade: IP67 Operating Temperature: - 40-+185 (- 40 -+85) Application: Ships, Yachts, Trucks, RV Note: Kind tips: 1. This type of fuel tank sensor is 240?33 ohm, only suitable for 240?33 ohm fuel gauge. Please make sure your product is suitable for 240?33 ohms before purchasing. 2. When the oil level or water level is empty, there will be 3?15mm space between the sensor float and the bottom of the sensor. This is a safe distance and the fuel sender will work fine. 3. Please check the size and description of the product carefully before purchasing, if the fuel tank is plastic, the length of the gas tank liquid level sensor should be 1in smaller than the depth of the fuel tank, if the water tank is metal, the length of the liquid level sensor should be smaller than the depth of the fuel tank 0.5in?1in