A catalyst system which can be used in the polymerization of propylene comprises at least one metallocene as a racmeso isomer mixture, at least one organoboroaluminum compound, at least one passivated support, at least one Lewis base and, if desired, at least one further organometallic compound. A method for admission control, an apparatus and a communication system thereof are disclosed according to the present invention. Heat is transferred at a first rate from the mold to a first portion of the body of molten metal disposed above the container.