You'll find you are going to need side imaging to find them. Once you are there, you'll need DI. A SI unit will have both. If you are going to buy just one, don't cheap out, you'll regret it.
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
2018 Robalo R180 CC, Yamaha 115
Bitter Gun Owner