This assembly is designed to be used with the Humminbird 360.  This is not compatible with the Humminbird Ice Fishing Pole.  The base with rail bottom mounts to either a 7/8 or 1 inch rail. The Aluminum Cross Shaft is 14"

The Humminbird 360 shaft slides into the 14" shaft assembly, which can be tightened. It comes with a depth collar so you can always set the transducer to the desired depth. When traveling you can rotate the assembly 90 degrees so the transducer is out of the water and secure.