Herring Bone Weave Also known as 2x2 twill (imagine a weave where the wool goes under 2, over 2), the most popular weave in kit-car and motorsport circles. The standard weave used by Caterham, Westfield, etc. This is the weave to choose if matching existing factory components. Linen Weave Sometimes referred to as 5-harness or 1x1. This is a finer weave than the herring bone/2x2twill. Negligibly stronger and heavier than the 2x2 twill, very popular in Europe and with the modified car scene. Kevlar Famous for use in bulletproof vests but in automotive applications such as these, generally chosen due to the yellow tinge! Alutex Similar to linen weave but with a silver appearance. Popular when matching components with alluminium bodied or silver cars. Polyster Black fibreglass, none of the strength/weight advantages of the composite materials but significantly lower in price. Example Weight Comparison    replacement Caterham half-sidescreens Outside carbon fibre, inside black approx 380 gr. Outside carbon/kevlar, inside black approx 380 gr. Outside Alutex, inside clear approx 410 gr. Polyester uni black approx 520 gr Caterham Factory part approx 600 gr.