Humminbird's Down Imaging transducer is shoot-thru compatible.
The XNT 9 DI T is the transom transducer that comes with all DI models.
The XIH 9 DI T is the same transducer but comes with epoxy instead of the transom mount.
If you get a Humminbird DI unit, you can supply your own slow cure epoxy or do the liquid pool that some do in kayaks to put the transducer in.
Humminbird Helix 12 SI, 1198c SI, 1198c SI, ONIX 10 SI NT, 360, RC-1