Tegea manufactures plastic and rollers. The plastic part can be used as supplied, or it is possible to fit them on metal cores, bearings, etc. The outside of the wheels can be coated by vulcanization or shod pressure. For threads it is possible to immerse the bushings to improve the resistance of the threads. Any external shape can be made, whether straight, curved or convex, including indentations. Helical (also crossed), axial or radial grooves can be made.