Flat felled seams can be found on almost all jeans. Tough and durable, flat felled seams provide three stitch lines, two of which secure multiple layers of fabric. Flat felled seams also conceal the raw edges of the seam allowance, reducing the likelihood of fraying.
Today, flat felled seams are often used when a sporty look is desired. They are commonly found on skirts, casual slacks as well as shirts and blouses. In addition to clothing, flat felled seams are often found on accessories such as tote bags as well as many outdoor fabric items including tents, and backpacks.
Although flat felled seams are often used with heavy-weight fabric (such as denim) because of the layering involved, they may not be suitable for extremely heavy or bulky fabrics. Limitations are often determined by the capacity of the sewing machine. Until the seamstress (or tailor) is proficient with the procedure, using a flat felled seam on curves (such as placing a sleeve into an armhole) should be avoided.