Aspects Bird Feeders Hummzinger Hummingbird Nectar Guard Tips 2 Packs of 12 tips- 24 tips total Tips easily slide on to the feeding port on the underside of the feeder cover The flexible membrane in the center of each tip easily opens when hummingbirds insert their beaks to feed and close up tight when beaks are removed Prevent flying insects from contaminating nectar Works for a variety of Aspects HummZinger feeders