Add this optional vestibule to your Big House 4 convert it from a simple structure to a cavernous escape from the sun or an unexpected change in weather. This extra-large, pole-supported vestibule is convenient for those trips when you need more space for camp chairs, bikes, dogs and all the extras - grab it when you need the room, and leave it at home when you don't. Features: - Extra large pole supported front vestibule provides extra space and a covered entrance - Dual sliders and storm flaps on door zippers allow for ventilation while keeping inclement weather out - Awning-style doors can be rolled up and secured for easy access, or extended using extra guylines or accessory poles (sold separately) - Multiple buckles make integrating vestibule simple and secure - Compatible with Big House 4 - 2025 (TBH425) and 2023 (TBH423) models