The invention relates to a system (10) for transporting loose sterile closure elements (12) from the surroundings (14) of an isolator (16) into an interior (18) of the isolator, comprising a container (24) for storing a stock quantity of closure elements in the surroundings of the isolator, an isolator opening (20) and a collecting device (56) for collecting the closure elements and for providing the closure elements in the interior of the isolator, with a metering device (46) for controlling a target quantity of closure elements to be transported from the container through the isolator opening and into the collecting device.