I had a question about this, so I thought i'd add:
The Explorer Deluxe, as standard, comes with a smaller, diamond/parallelogram silnylon rainfly that just about covers the area of the hammock from from rainfall.
The one i'm selling has the optional upgrade silnylon "Hex" rainfly which is much larger. This has to be bought direct from Hennessy - and comes in either silnylon or PU. The silnylon is much lighter, packs down much smaller and wears better than the PU one.
Basically, you can comfortably sit/lounge around under the general area of the Hex in the sun/rain - and under the standard parallelogram rainfly you'd be stuck directly underneath your hammock, and things would be tight. The big Hex transforms the hammock from a single-use sleep system to a large, very liveable camp area.
The size/shape of the Hex also envelops the hammock when needed- so you can really batten things down if it's due to be a wet night.
Hope that helps.