The Bosch OSL350SPD Starlock Oscillating Triangular Sanding Disc is a triangular plate for attaching triangular sheets designed for detailed grinding. This overlay features a 3D Starlock interface for tools and accessories which provides a larger contact area than a flat interface for best-in-class grip and maximum torque transfer. Bosch triangle sanders are also suitable for material removal and surface finishing of multi-purpose plywood , hard and soft wood.