The two upper screws on the binding allow you to adjust the fold of the fabric and set them at the same length for a straight stitch or set the bottom a bit further than the top for a blanket stitch. We supply 1 year warranty, 30 days money back, 7x24 hours email support. If you have any problem, please don't hesitate to contact us, we will try our best to solve it for you. Suitable for all brands of sewing machine and computer sew machine, you need to replace the presser foot, needle plate and teeth when use. It is a sewing tool which can aid in creating a tape-like fabric which can be attached by sewing the edges of any sewing project. Sewing machine binder is made of high class stainless steel with high strength and -resistant. Easy to install without other special requirement.