The Superdome Bivvy Extended Wrap is a dedicated overwrap which traps a layer of air around the shelter, aiding in elimination condensation and increasing heat retention when using the Superdome Bivvy. It can be easily fitted to the bivvy by a lone angler, in much the same way that you would put an overwrap on any Armo or SLX-style bivvy.
Due to the large peak of the Superdome Bivvy, using the Extended Wrap creates a large porch area of approx 50cm in depth, which is can be used as additional storage space for things like waders, dirty boots, bait buckets, etc.