The CA50B-9B is a 1kW Single Frequency 50kHz Transducer that has a beam width of 12° x 28°. The B260 is also a 1kW transducer that is dual frequency of 50/200kHz, keeping in mind that the 50kHz side has a beam width of about 19°.
So, the CA50B-9B has the larger beam width, where the B260 is going to have the slightly smaller beam width. Both transducers have 50khz Low Frequency, and both have the same 1kW output power that will provide you about the same depth performance.
So it all comes down to you choosing for the larger coverage area, then you can go for the CA50B-9B. If you are looking for the better target separation (better resolution) then choose the B260.
Both transducers have the same frequency of 50kHz, and both transducers have the same transmit power of 1kW. So it's all going to come down to the transducer's beam width.
The CA50B-9B is widely popular transducer for use with the US West Coast Commercial Fishing Fleet engaged in deeper fishing.