arrow 15 at the entrance 16 of the interlock chamber 33 obtains atmospheric pressure here uncoated synthetic bottles 17 18 19 are placed onto a not shown linear conveying device which subsequently transitions into an annular conveying device the bottles located on the conveying device are hereby moved from the atmosphere into the high vacuum of the coating chamber 30 here the bottles of which some are provided with reference numbers 21 to 25 by rotation about their longitudinal axis indicated by an arrow 28 are again transported to a not shown linear conveying device with the aid of which they are guided past the magnetron cathode 32 or past a series of magnetron cathodes from the aluminum targets of these magnetron cathodes metal particles are sputtered off which subsequently react with oxygen and nitrogen hereby aluminum oxynitride is deposited on the outside wall of the bottles all of the bottles in the vacuum coating chamber 30 rotate continuously about their longitudinal axis and specifically at least at such a rate that a 360 u00b0 rotation is completed before the bottle has moved passed a magnetron cathode 32 a more uniform distribution of the coating is obtained if the rotation of the bottle assumes a multiple of that cited at the end 26 of the right side coating path the rotating bottles carry out an about turn of 180 degrees.