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Brother Bobbin case.
Part Number: XG2058001
Guaranteed to fit because it is a part.
The bobbin case can be adjusted when bobbin tension changes are required to accommodate different bobbin threads.
To adjust the bobbin tension for embroidery function, using a slotted-head (-) screwdriver turn the slotted-head screw. DO NOT turn the Phillips screw (+). When the bobbin is set at the correct tension the upper thread slightly appears on the wrong side of the fabric.