0.4mm (0.016") x A4 This is a sheet of carbon fibre (or carbon fiber if you prefer) which is the size of an A4 sheet of paper.... Manufactured here at our works by laminating and compressing two layers of 200g woven carbon fiber (fibre) fabric under a vacuum and curing the product at 120 Deg C, which produces a 0.4mm (0.016") thickness (16 thousandths of an inch)