Bivys are lighter than tents, pack smaller than tents and are easier to set up than tents. They don't, however, have the comfort of a vestibule. The Sil Tarp can be your solution. The Sil Tarp is a silicone-impregnated ripstop nylon tarp that can act as a raincover over your bivy entrance. You can put on your boots, cook and sit out of the rain under the Sil Tarp. In a pinch, it serves well as a footprint, and is great alone to take without your bivy as an emergency tarp. Integral now offers three sizes, a 5 ft.x 8 ft. tarp weighing only 7 oz, and a 8 ft.x 10 ft. tarp weighing 14 oz, and a 10 ft. x 12 ft weighing 22oz.