The HH2O: the next evolution of the idea to tension the fly with rocks or other weights is to clip a funnel onto the two side "O" rings of the rainfly. The narrow end of each funnel is threaded to screw onto a hydration water bag or any size of pop bottle. As the rain water drips off the low corners of the rainfly into the bottle the weight of the water in the bottle lowers the fly automatically for storm conditions maintaining tension on the fly and giving you several liters of water ready to go in the morning. . Just another way to make your Hennessy Hammock more useful. Fine-tuning the production of this design has taken a little longer than expected but we think you will find it well worth the wait. Patent pending. We suggest that you filter the water if you will be using it for drinking or cooking.