Hey guys. I'm a newbie. i just bought a "94 Sea Ray 400 EC. From what i can tell it's had a couple of different electronics packages installed over the years. I have a manual for a Lowrance LMS-350A and a B&G LCD Chart but I don't have either device. I do have a Garmin 421s that came with the boat. I took pictures today of what I believe are 2 or possibly 3 transducers and I was hoping someone could help me identify exactly what they are, if they are thru-hull and if they will work with the Garmin412s. Thanks in advance for your help.