This topic would have been better placed under the sounders area where most of the sounder/transducer experts hang out.
The SS264N consists of two transducers (purchased separately):
SS264 50 kHz wide-beam 25°
SS264 200 kHz narrow-beam 6°
If I recall correctly the 200Khz unit will connect to the 50khz unit and then the 50khz has a combined cable going to the sounder for 50/200. It is should work. Normally, one freq is placed on one side of the keel and the other on the opposite side of the keel. Personally have never been a big fan of the 164/264 housing type transducers. Placement and following the installation instructions are very important on these. Never put them on a boat larger than 36 feet because of the boundary layer and ensure they are in an area to pick up clean water without turbulence.