Its a 2amp. There were 3 or 4 threads about this on IS this year. The consensus was that they added it this year. You might want to call marcum and ask if you can go to a 3amp. 3amp is standard for sonar units, and I’m surprised marcum is still using 2amp after their issues with the showdown’s 2amp fuse blowing. One guy posted that marcum said it was okay to use a 3amp, but I’d call and hear that from the horses mouth first.
If you are going to stay with 2amp, buy a 5pk and keep them handy. ANY hardware store will have 3amp, 2amp MIGHT be hard to find at some stores.. but you’ll be able to find them locally. Its just a plain auto-style fuse like what is in car/boat fuse boxes.