I can't seem to find any info anywhere about what inline fuse size should be for an old school dial flasher. YES, I HAVE LOOKED IN THE MANUAL and it mentions nothing about that. I seem to possibly remember many years ago on my other units it was maybe a 1 amp, not sure tho. No info anywhere. This unit i have now is about 50 years old and brand new , just removed out of the sealed box. Never used. I am installing it on my Jon boat and I just cannot remember the size from yesteryear.