Thank you for viewing. This is an offering for the Rec-Mount 17mm Ball Attachment, compatible with bike navigation systems, REC17-A17. I purchased it for installation but didn't have the opportunity to use it, so I'm putting it up for sale. This is a 17mm specific product. If the size differs even by 1mm, such as 16mm or 18mm, the ball will move and it cannot be used. Please confirm the dimensions of the parts currently attached. When shipping, the ball part will be disassembled. (It's a screw-tightening type.) 【Condition of the item】 I tightened the ball part once, so I selected "Like new" for the condition, but it is in a clean state. I hope to sell it to someone who needs it. Please purchase only if you understand that this is a used item, as it has been inspected by an amateur and stored at home.