The Brother SA231 Dual Function Fold Binder for CV3440 CV3550 Cover Stitch Machines is used to fold 1.25 inch (32mm) wide bias fabric tape into 0.31 inch (8mm) wide double fold bias tape, and then apply the bias tape binding to the edge of fabric. Attach the Brother SA231 Dual Function Fold Binder for CV3440 CV3550 Cover Stitch Machines to the cover stitch machine simply with the two included screws. The Brother SA231 Dual Function Fold Binder for CV3440 CV3550 Cover Stitch Machines may also be used as a binder for single fold bias tape. Tweezer is included. The Brother SA231 Dual Function Fold Binder for CV3440 CV3550 Cover Stitch Machines is compatible with models CV3440, CV3550