I don't know where these come from. Tool can be moved anywhere in the world and run. This is expensive to get into, it's a pretty intricate design. Tool would certainly be a multi-cavity mold. Hard to guess. I was involved in injection molding, larger parts. Very competitive business.
Larger parts, more costly to ship tend to (obviously) be made closer to the end user.
The cassettes I have purchased are nicely made.
With the mess of the pandemic it wouldn't surprise me if these were manufactured in N America, Canada has all kinds of shops that could mold these.