This specification describes the characteristics of a ca. 270 g/m 2 balanced bi-axial woven glass roving, which consists out of a 135g/m 2 0? and a 135/m2 90? layer. The E-glass (? = 2.6 g/cm?, E = 72 GPa) is finished with an epoxy-compatible (bisphenol A(/F), amine cured) seizing. The filaments of the glass fibres have a diameter of 17  ? 10% ?m (or less).