The top vent covers for the Igloo/Bubble Dining Domes can get detached and blow off if they’re not secure. This is a clear round replacement cover made of the same PVC material as the main cover. It will fit over the top vent hole with quite a bit of extra overlap.
To secure it, we suggest using an adhesive like E-6000 (available at any Home Depot or Hardware store). Apply the adhesive to the dome cover itself in several places, then center the vent cover over the hole and let it dry for about 5 minutes. It should never come off again.