The present invention concerns a dustproof mechanism for a detecting means comprising comprises a detecting position, through which substances to be detected are passed at a prescribed position of a detecting optical path, which is formed on one side of the detecting position. In one embodiment, updated context information from a previous segment is used to transmit a next segment. The latch holds the hook in the connector, and the resilient loop presses against the hook to keep the hook pressed against the latch when the AGP display interface card is mounted in the socket. The lower case has a plurality of hollow positioning plugs placed in a manner so as to be correspondingly received by the retaining pieces for firmly retaining the positioning plugs. The outer member length is substantially coextensive with the length of the elastic inner core unitary stretchable main body unit.