I've started using these sanding disks on my random orbital sanders and they work better than any others I've tried.

For hook and loop try these. The 80 grit 5" dia. is part # 4195A11 at this link

http://www.mcmaster.com/#4195a11/=2a65ub

For adhesive backed version try these. The 80 grit 5" dia. part number is # 4675A53 at this link

http://www.mcmaster.com/#catalog/115/2624/=2a67rq