ICM Professional Superferro - 1980 - EU
ICM were the only Swiss cassette brand that I know of.
They made many cassettes for others, shells and hubs too. Their hardware was well renowned for their Swiss prescision.
The tape usually came from Germany, either BASF or AGFA.
These exceptionally rare and retro Professional Superferro are the business! Best used with some NR, these sound really good. The bass is exceptional and the treble nice and clear.
Here's a review:
They also have the worst J-Card ever, but I guess if they were designed for professional use, that wasn't a problem.
But damn, with that big window with the gold, how fine do they look 😍