Square style seat bag with a low center of gravity and recommended for campers A seat bag with a square style that uses molded panels on both sides and has a low center of gravity and excellent loading stability. The square and flat top surface is reinforced with a resin plate, so you can safely stack them on top of the bag. The upper flat top has waving tape on all sides, and is compatible with carabiners, J-shaped hooks for adjustable bungee cords, and RR9976 Grimlock to support stacking. The capacity is 32.5L at normal time, and can be increased to 40L at maximum by expanding the left and right sides. A resin plate automatically extends on the bottom of the expansion part that increases the capacity of the sides, and it has a safe structure that prevents the load from collapsing due to sagging on the left and right sides. The width can be expanded to 50cm, making it suitable for storing long items. Long items over 50cm can be secured with the external hold belt. The inner frame structure has molded panels on both sides to adjust the shape, and resin plates on the other sides to prevent the load from collapsing and protect the stored items. A friendly design with open zippers on both sides, and a side-open type that allows you to put in and take out items from both sides without using the top slot even if you load the bag at the top. The inside of the side panel has a mesh inner pocket with a gusset. The rain cover is stored in a special pocket on the back and can be connected to the bag itself with a buckle, so you don't have to worry about the cover flying off. If the standard loading belt is installed on the vehicle body, it can be attached and detached using only the buckle.