The Garmin 300C has 1 plug in the back of it that locks on to the depth finder, then it splits off to transducer and the battery. its very simple to use and has alot of features you would find on the more expensive ones. It works in depth from 1ft to 900ft. It has dual beam transducer, ultra fast scroll,and has alerts you can set for fish size and water depth. one of the features I really liked is that it comes with a bracket you can mount the transducer right on your trolling motor. No need to drill holes in the boat.