RAM® Ball Adapter with 1/4"-20 Threaded Post - B Size – RAM Mounts
RAM-217U RAM Mounts 1.5" Double Ball Adapter with 2.5" Round Base - Synergy Mounting Systems
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Amazon.com: BRCOVAN 2 Pack, Aluminum Alloy Mount Base with 1'' TPU Ball & 10mm Mounting Hole, Angled Bolt Head Adapter Ball Base Compatible with RAM Mounts B Size 1 Inch Ball Double
Motorcycle - 1" Ball Adaptor - Quad Lock® USA - Official Store