Dual freq. transducers by Lowrance are set at 50/200khz.
The LMS 332c is a single freq. 200khz.
If you plan on doing more salt then freshwater fishing, go with dual freq.
If freshwater is your major choice, a single 200khz. will do the best job.

50khz. advantages
ADVANTAGE better penentration in salt water
ADVANTAGE better for depth that might exceed 200"
DISADVANTAGE less seperation of targets., ie fish off bottom, seperating fish that are close together.
DISADVANTAGE tends to over saturate screen when used in shallow water

I have had the advatage of trying several different  transducers this year, I would be glad to pass on my findings, give me a call, too much to info to type out.
Larry Gonczy

thank you larry