Those are on eBay, and even Amazon.About 25 years ago, Radio Shack/Tandy changed the label and box, and called it "Bulk Disk Eraser".
The college bought one, and discarded mine.
But, as everyone knows, the one SURE way to totaally erase a disk is to store the only copy of something irreplaceable on it.
-- Grumpy Ol' Fred ci...@xenosoft.com