It depends on how you want to use your depth finder. If you have one on the console with the transducer mounted on the transom then the question is do you want a DF up front with the transducer mounted up front? If so, then the US2 provides you with a built in transducer in the motor with the cable internal to the shaft so you are not fighting with loose and twisted cables on the TM. If your garmin is mounted up front then where is the transducer mounted? If it is on the transom and you are happy with it back there then you do not need the US2. But if it is up front and you want to have the transducer up front, the US2 will let you do that. You have to purchase a short cable adaptor from MK to hook your garmin to it. This is true no matter what kind of DF you have. The US2 will work with most all DF but you have to have the interface cable to hook the DF to the lead from the motor. Also, the US2 only works with regular 2D and some DI (down imaging) units. It will not work on a SI (side imaging) unit because the movement of the transducer on the TM distorts the image on the screen. My short answer would be if you want a DF up in the front of the boat and want to see what is right under you (not 15 or 20 ft. behind on the transom) then the US2 is the way to go. Hope this helps.
