You can use the XHS 9 HDSI 180 T or XTM 9 HDSI 180 T. Do a web search for the best price.
Last one I purchased was from Walmart on-line.--MSRP is $270 and you can find them for under $200.
Same HDSI transducer that is used up to the MEGA SI models.
Edited by Wayne P. (10/03/17 02:04 PM)
Humminbird Helix 12 CHIRP SI, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2, SOLIX 12 SI, 360, RC-1