Features: 1.Unique Deisgn: 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. 2.Material: 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. 3.Features: 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. 4.Compatibility: 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.Installation Suggestion: If the fuel tank is plastic, the length of the sensor should be 1in/2.5cm smaller than the depth of the fuel tank, if it is metal, it should be deeper than the tank 0.5-1in. Specification: Item Type: Fuel Sending Unit_x000D_ Main Unit: 316 stainless steel_x000D_ Cable: PVC_x000D_ Float: NBR_x000D_ Installation: Standard SAE 5 hole type_x000D_ Screw Size: M5 x 0.8_x000D_ Aperture: Approx. 5 mm / 0.20 in_x000D_ Product Size: Approx.8in/200mm_x000D_ Recommended Water Tank Size:8.3-9in(210-230mm)_x000D_ Output Signal: US standard 240-33ohms (240ohms without load, 33ohms at full load)_x000D_ Resolution Range: Approx. 21mm/0.83in_x000D_ Fuel and Water Level Sensor Type:Resistance_x000D_ Alarm Switch Rated Current: 500mA_x000D_ Protection Class: IP67_x000D_ Operating Temperature: -40F ~ +185F (-40C ~ +85C)_x000D_ Application:_x000D_ Suitable for boats, yachts, trucks, RVs Note: 1. This 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._x000D_ _x000D_ 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._x000D_ 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 0.5?1in