4° Wedge for Under Vision Mounting PlateWhile underway the bow of your powerboat tends to ride at an elevated angle, causing your radar to be angled. With Edson's 68810 4 degree Wedge for under Vision Mounting Plates the elevated bow will be offset aligning your radar to see better. Edson's 4 Degree Wedge requires an Edson Mounting Plate and an Edson Vision Series Mount. Order Base Mount and Mounting Plate separately. Specifications5.313" x 5.063"3" Inner Diameter