The probe is constructed of concentric tubing (a small tube inside a larger tube). The tubes, which are separated by small insulators to keep the tubes from touching, acts as a capacitor that has one value in air (empty tank) and changes in value as the fuel level rises inside the probe. The amplifier converts these values to a signal suitable to drive a standard meter or other display device. Can be manually calibrated. See Documents tab.
12 or 24 inches with 3 inch bend
Yes this has the 5 hole pattern. We suggest having the product in front of you before making any changes or modifications.
Per the datasheet, the outer tube is simply a ground for the inner tube that does the sensing.