Pipe to Fold-Down Adapter 3-1/2″ Mast Edson’s Fold-Down Adapter 3-1/2″ Radar Masts attaches to the bottom of your radar mast allowing it to fold down. Fold-Down Towers are perfect for trailer boats, low bridge clearance and end of the season storage. By using a992-35 Pivot Bracket (sold separately) and Fold-Down Adapter with your Standard Radar Mast, you can also mount your radar on a raked transom or coaming side. Use 989-1 Right Angle Base (sold separately) if mounting to a vertical surface and folding tower fore and aft.