Adapter Plate for Simrad HALO™ Open Array Radar Use for Modular Mounts - ADA-R1 Required
The Seaview Top Plates are made from a pre-drilled plate that has been incased in a UV resistant ABS plastic.  Drill templates come with all Seaview Top Plates.  Simply drill the holes that are marked to your specific Simrad electronic.  This makes for a very clean installation with no unecessary holes. 
Specifications: