Geoff,
How many customers of (directional) aftermarket fuses are there since they first came out 15 years ago? 100,000? That’s a whole lot of typical people who can hear wire directionality.Of course, I am skeptical that those folks actually hear the direction of their fuses rather than the psycho-acoustical effects of cognitive bias or loss aversion based on marketing hype and the fact those items cost more than the "regular" fuses some of us unenlightened folks use.