Mestool 58-AP Gold 5-Inch 8-Hole 80 Grit Dustless Hook&Loop 100-pack (80)

What does the quantity mean? is that the grit? why do i need to select that? doesn't the 100 pack have all them in there?

Does the "hook and Loop" mean that this will work on a Ryobi that takes self-adhesive disc's? Thank you

Will these fit with the Mikita BO5041?

Where is this product made?