Feature: 1. Characteristic: All fuel sending units consist of a selection of reed switches and fixed resistors. SAE 5‑hole mounting mode, heavy duty 316 stainless steel, solid structure. Signal output: 240 ohm ‑ 33 ohm. 2. Application: The fuel level sensor can support the fuel level gauge and tank level gauge of the ship, RV, truck, equipped with washers and mounting screws to prevent the sensor from contacting the bottom of the tank, 3. Long Lasting: The advantages of this doughnut float type level sender over the thick film swim arm type level sender lie in the durability and reliability of the reed switch. There is no need to adjust the tank. 4. Installation Instructions: if it is a plastic fuel tank, the length of the sensor should be 1in / 2.5cm less than the depth of the fuel tank; if it is a metal oil tank, it should be 0.5‑1 inch / 1.25‑2.5cm deeper than the fuel tank. 5. 35mm Float: The float has a diameter of 1.38in (35 mm). If a hole must be drilled, a 1‑1/2in (38mm) diameter hole will be perfect. The sender has a non linear output, which can only be matched with the standard instrument with non linear signal. 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 10in(250mm) Recommended Size Of Water Tank: 10.3-10.8in (260-275mm) Output Signal: US Standard 240-33ohms (240ohms At No Load, 33ohms At Full Load) Resolution Range: 21mm 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. Package List: 1 x Fuel Sending Unit 5 x Screw1 x Gasket 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