Om sure this has been discussed many times, but...... I just bought an older 17 ft tracker with 0 sonar on it. I have 2 lowrance elite 4 units, 1 color with gps, the other an elite 4x not color not gps. I plan on putting these on my boat, one on my trolling motor the other on my console. both have transducers that I know nothing about, and this will be my first time setting up and attempting to truly use sonar. Looking online is ridiculously overwhelming, can somebody give me some basic info, setup suggestions? Are these units servicable?