i guess you couldnt get much more portable than the new smartcast rf20 and rf30 , one is a wristwatch with a transducer that hooks to your line and the other aone that hooks to your pole and a casting transducer , how cool is that if they work they say there good from 100 ft and a 100 ft depth range and a 400 hr transducer charge also they have a couple other units that work with these transducers , i believe they will work with any matrix series hummingbird systems