width does matter also the 20mm wide ones won't always fit where 18 is required, I agree it looks like standard 90x18, that's a common size, here are some:
worth also checking the pin size but I expect that'll be your typical wheel. The brake pads vary by the wheel manufacturer not the bike so much, instead of searching benelli blazar brake pads, look at the wheel id it a grimeca snowflake wheel? Leilu spokes? but yea, better than that is measuring, which you've done, and it's 90mm, probably 90x18 wide, so get those, rip, stop, party.