A fused collar means the interlining is heated and glued together through a fusing machine. A stiff, firm collar is favored with most dress shirts and the fused collar provides the best results, making it a popular choice. Fusing or otherwise known as interfacing  gives support and stabilizes areas of a panel ready to be attached to a garment e.g. cuffs and collars. Perfect for bespoke shirting, this material combines durability with an exceptionally soft finish.