Filler spools Designed for optimum strength and casting distance. Smooth for long and quiet casts 0.10 mm class 0.004 in class 9.0 kg 328 yd 300 m The Berkley x9 braid is a braided cord made from 100% PE fibres. 8 braided fibres are widely used. Berkley x9 takes it to a new level by adding an extra fibre. The x9 is therefore extremely strong and tear-resistant and made so that it is supple and can therefore be thrown effortlessly and far.