Abstract: Centrally apertured discs which are to be subjected on one side to a treatment such as the deposition of a layer of material on the disc are carried on disc holders in a magazine which comprises a pair of opposed parallel walls and which has an open side between these walls through which the disc holders can be inserted in and removed from the magazine. The disc holders each comprise a rigid plate and attachment means for attaching a centrally apertured disc to each side of the plate, the attachment means engaging in the central aperture of each disc. The plate has at least one pair of opposed parallel edges for cooperation with guide rollers which are provided on the inner sides of the opposed walls of the magazine for guiding the disc holders during their insertion in and removal from the magazine in directions parallel to the opposed edges of the plates.