Abstract: A tubular extruder for extruding an elastomeric material mixed with short fibers into a tubular form, with the short fibers circumferentially oriented, a cutter for axially cutting the tubular elastomer, and a development unit for developing the tubular elastomer with a longitudinal slit into a flat form are provided. Arranged between the extruder and the cutter is a guide unit used to guide the tubular elastomer with the help of its tubular section. Air is blown off from the tubular section of the guide unit whereby the tubular elastomer is cooled while at the same time its shrinkage in the circumferential direction is suppressed. The ununiformity of shrinkage is avoidable and the disorientation of short fibers is prevented.