Second Channel Add-on Pack for Ultrasonic Antifouling Kit for Boats

via Jaycar
Refer: Silicon Chip Magazine May/June 2017 
This is the add-on kit to make the KC5535 Ultrasonic Anti-Fouling Kit For Boats into a dual channel, so it can work on boats up to 14m.

For more details see KC5535

Kit includes all specified parts to make the second channel, including one transducer. 

Assembly required
Warranty: 12 Months