An apparatus for heating plastics material pre-forms includes a conveying device which conveys the plastics material pre-forms along a pre-set conveying path (P). A plurality of holding elements for holding the plastics material pre-forms and a plurality of screening elements for screening off heat are arranged on the conveying device. The apparatus has a plurality of carrier units on which at least parts of the holding elements and at least parts of the screening elements are arranged and these carrier units are capable of being removed from the conveying device jointly with the parts of the holding elements and screening elements which are arranged thereon.