The latest offering from Radarsonics Inc. is the Model 250.  The Model 250 offers the maximum performance for your boat in a high speed transom mounted Transducer.  In addition, the Model 250 is designed to be easily retro-fitted on to vessels that have either the Model 231, Model 236 or Model 238 installed.  Just remove the mounting hardware and replace the Transducer, as the  Model 250 employs the same mounting footprint.