Straight styli are used to detect easily reachable features on the measured surface. Because of the specific surface properties of contact points made of zirconium oxide - a ceramic compound with high wear resistance – they are acknowledged as the best choice for aggressive scanning of abrasive surfaces, such as workpieces made of cast iron. Zirconium oxide provides a smooth and frictionless sliding performance on rough surfaces. Carbon fibre, the very lightweight and extremely stiff high quality material, with a thermal expansion coefficient close to zero, is particularly suitable for the manufacture and application of long styli and extensions.