Arkon SP92AMPSPLATE Square Mounting Backer Plate Adapter with 4-Hole AMPS Drilled Base Pattern (sku 59207)Provides a solid mounting surface when attaching a heavy duty mount to a soft or porous surface Metal backer plate features recessed pre drilled holes in the 4 Hole AMPS pattern Screws not included Use SP92AMPSPLATE to create a solid mounting surface when attaching a heavy duty mount to a soft or porous surface, such as a dashboard. This square metal backer plate measures 3. 625 x 3. 625 x . 16 inches (92 x 92 x 4mm) and features off center recessed