Here’s another that will help any finder. I installed the an Airmar P66 transducer on my Lowrance. Picking up more in the water column has greatly improved over what you don’t see on the finder with standard transducer. And no it doesn’t increase fish catch. When I bought my Raymarine A57D it came with an Airmar P58. That was the first thing I was going to do to replace the stock transducer but was surprised it came with an Airmar. Cost comparison when replacing is close to unit manufacturers cost for the transom mount. Airmar thru the hull is a little more pricey.
Here is a contact of a guy I do and several others do business with when it comes to your boating electronics and the prices are within scope.
Gil Travis
Marine Electronics Sales
1-800-925-0341