The IBNS upgrade kit was designed based on feedback from U.S. Marines, and is made to give protection from wind and rain. In many of the sub-tropical and tropical zones where our Marines are deployed, rain and wind can come with little notice, so the Marines asked for a easily-addable, secure, and waterproof fly that could be added to the IBNS at a moment's notice while still allowing for ventilation. The IBNS upgrade kit was Catoma's answer to their feedback.  Durable: The EBNS fly is made of 70 Denier 1.9 oz. ripstop nylon.  Lightweight: The EBNS fly weighs a mere 40 ounces. Increased insect repellency: The fly is permethrin bonded, adding to the repellency of the IBNS.  Waterproof: The EBNS is 1200mm waterproof.  Flame retardent: The EBNS is CPAI-84 flame retardent rated. 

The EBNS measures 68" x 100" when fully deployed.