The RaceQuip 121 series multi-layer SFI-5 racecar driver's fire suit jacket is made up of an outer layer of durable Pyrovatex® FRC, backed by a layer of Nomex®, then lined by another layer of Pyrovatex®. Note that sometimes these materials are referred to as "fireproof", but all auto racing safety gear is "fire retardant". Pyrovatex® offers the maximum combination of overall flame and heat protection, durability and comfort for the price. This fire-retardant cotton based (FRC) material is used for the inner and outer layers because it retains the softness and breathability of cotton and will wick away moisture from the skin. Pyrovatex® fabric is gentle and non-irritating to even the most sensitive skin. The treatment process leaves the exterior surface shiny and supple. Since the Pyrovatex® process combines a chemical agent with the raw cotton fibers to create a bond at the molecular level, with proper care; the jacket will retain its flame-retardant properties beyond the useful life of the garment. The middle layer consists of Nomex(R) batting which is an inherently fire-retardant aramid fabric. All racing jackets are assembled with heavy-duty, multi-needle, over-lock safety stitch machines to provide exceptional seam strength.