Have strong wear resistance and can more than 100000 cut under normal circumstances, which significantly reduces the replacement frequency and maintenance cost Ideal for home sewers and small garment workshops requiring professional components for heavy duty projects This set reduces maintenance frequency through wear resistance and edged retention for continuous sewing workflows This metal sewing machine upper & lower 5020700407 5020700620 deliver superior cutting, crafted from hardened alloy steel for extended durability handles daily fabric processing tasks from clothing alterations to drapery creation maintaining edged through dense materials like upholstery textiles