o The models 504/505 are orbital sanders with a 3/32″ offset.o The smaller rectangular orbit allows better sanding access for bumpers, recessed areas, and new panel prep. o Both sanders use standard 2-3/4″ Velcro sandpaper rolls. o Velcro pads securely hold scuff pads for easy new-panel prep. o Built-in pad release feature. o Models 504 2-3/4″ x 4″ Velcro pad models 502 2-3/4″ x 5-1/2″ Velcro Pad.