Superlight Bivy

Mountain Laurel Designs builds the Superlight Bivy specifically as a protective layer for tarp campers rather than a standalone storm shelter. Constructed with a water-resistant, highly breathable nylon top fabric and a waterproof bathtub floor, it shields down sleeping bags from windblown rain, spindrift, and ground moisture. A hood section with integrated insect netting keeps bugs off your face, while an overhead hang loop can be tethered to a tarp or trekking pole to lift the mesh away and reduce claustrophobia.

In the backcountry, the bivy functions as both a vapor and thermal regulator. Layering it over an ultralight quilt reliably adds several degrees of warmth while blocking lateral wind drafts that typically sap heat from an open tarp pitch. Breathability is among the best in its class, venting interior moisture far better than fully waterproof bivy shells, though persistent rain combined with freezing temperatures will still cause some footbox dampness if site ventilation is compromised.

Packing down roughly to the size of an apple and weighing well under six ounces depending on configuration, the design sits near the pinnacle of gram-saving shelter systems. Compared to simpler rectangular bivies like those from Borah Gear, MLD offers a more anatomically contoured mummy cut and meticulous reinforcement at high-stress seams. For dedicated three-season thru-hikers and fastpackers who live under flat tarps, it represents a proven balance of protection, packability, and durability.