The new Delta RW 6 Fabric is made from a mixture of very comfortable soft fibers by means of a processing method known as "body-size" in which the garment is produced as a single piece item with no stitching at the sides. This type of process means different sections can be made more or less elastic to meet different needs. The existence of more elastic sections makes the garment much more comfortable to wear.Sparco Delta Rw 6 Bottoms, FIA approved underwear. Light, comfortable and breathable. Body Fit manufacturing process means they are a single piece meaning no seams or stitching at the sides.