Borah Gear Cuben Bivy side zipperBorah Gear Cuben Bivy side zipper This is the lightest bivy from Borah Gear, weighing only 120g in standard length and girth and with side zipper. This bivy is for the true ultralight backpacker who wants to save as much weight as possible and carry minimal volume. The zipper goes across the chest and then takes a turn down the left side for approx. 51cm (20"), creating a bivy that is easier to get into. It is one versatile piece of ultralight gear