Abstract: A connector system is disclosed for providing a connection between a tubular connector having external projections and a mounting collar having a hole with internal notches, for receiving the projections and securing them upon rotation. The connector opening has a non-planar edge and the collar includes an elastic sealing diaphragm with an elongated hole. This configuration of elements cooperate to reduce full contact between the diaphragm and connector during installation, permitting less force to be used in bringing the components into full connection and also providing a spring force which facilitates removal. Also disclosed is a bag for receiving a connector portion. The bag has a continuous perforation, approximately dimensioned to correspond to the connector portion's opening. The perforation is separated by contact with the connector, so as to admit the connector into the filter bag.