Beanbags provide a convenient support to wildlife photographers working from a vehicle. Working from a car allows you to get much closer to birds and mammals, but you need to support your telephoto lenses for sharp pictures. The H shaped design of this Beanbag allows it to grip the door instead of sagging. Even the window glass will support it allowing the camera height to be altered by winding the window up and down. It is a great improvement on a standard beanbag. Approximately 22cm square it is in effect two bags sewn together allowing the contents to move from one half to the other, which creates the gripping action. It is made of a tough green camouflage DPM material. This bag is now supplied full of Polystyrene. It has a zipped entrance should you ever wish to change this. Two tabs are attached so that the bag can be tied to a vehicle in case it should fall to the ground. This bag is also available on the Amazon web site empty ready for filling with beans or rice etc. Search for B005PHHKVK.