I just bought a lms 520 wich is better than the 522 because the 522 is a dual freqinze where the 520 is not wich gives you a better bottom degree of 60% insted of 20% wich i was told by a lowrance tech.I was told for fresh water fishing the 520 will be better than 522 for me.Hope this helps.I would call lowrance and ask yhem wich one will better suit you between the 2 the lms520 or lms522.