A separation or reaction unit (1 1′ 81 81′ 101) and a method for aseptically connecting such units. The separation or reaction unit (1 1′ 81 81′ 101) comprises at last one fluid inlet (3a, 3b, 5a, 5b 3a′, 3b′, 5a′, 5b′ 85a, 85b 103a, 103b) and at least one fluid outlet (3a, 3b, 5a, 5b 3a′, 3b′, 5a′, 5b′ 85a, 85b 103a, 103b). At least one of the inlet or outlet is sealed by at least one film (7, 9 11 87a, 87b 107a, 107b) and the contact surface between the film and the separation or reaction unit is aseptic. The films are adapted to be mated with a corresponding film on another separation or reaction unit or on a fluid distribution unit (20 57 61) which the separation or reaction unit possibly should be connected with and said mated films are adapted to be pulled out together two and two after mating such that corresponding fluid inlets/outlets on the two connected units are mated aseptically.
