The solid investment-cast 316L stainless UM6080 was designed primarily as an adapter for mounting downriggers. When your downrigger is not in use, you can use that mount location for another boating accessory like a flush mount rod holder or a flag. The UM6080 is equally useful as a BBQ, bait board, or other custom adapter. The 4-hole pattern is a 2.5" square with ΒΌ-20" threaded holes. Cannon (TM) downrigger mounts Part #1903003, #1903004, #2207002 and #2207323 will bolt directly onto the UM6080. Other downriggers will need the addition of Burnewiin adapter plates. Please review our adapter plates to choose which one you may need. Let your imagination go and create other uses for this versatile adapter. The UM6080 is NOT compatible with the GM400 Mount.