FESTOOL Interface Sander Backing Pad IP-STF-D90/6For RO 90 DX. For profiles and contours. The extreme softness provides smoother surfaces. An extremely soft pad, the foam interface pad allows the abrasive to float on the surface, producing smoother results on delicate profiles and contour. For superfine sanding, the interface pad absorbs the energy of the user and the machine, leading to less abrasion and a higher grade finish. StickFix hook and loop design for quick and efficient abrasive changes;