Fishfinder 90/140 Owner's Manual, mounting on a transom - test | Garmin Fishfinder 90 | Owner's Manual (Page 31)
Amazon.com: Kayak/SUP Transducer Mounting Arm with Marine Electronics Fish Finder Base Adapter Ball Mount, Compatible with Scotty, Lowrance, Garmin Fish Finder : Electronics
Garmin Fishfinder 90, 140, 250 e 160 - YouTube
Understanding Dual Beam Transducer Coverage, area of about a 7-foot circle. - w dual beam | Garmin Fishfinder 90 | Owner's Manual (Page 8)