Tillett B4 Carbon/GRP Race Car SeatThe B4 seat weighs 4. 9 kg and has been made to allow fitment into some of the narrowest vehicles around. Although light, it is still rigid due to its twin skin construction and it holds the driver in a reclined "formula style" racing position. This version of the seat is made from GRP with a layer of carbon fiber on the seating surface and the edges of the seat are kept on for added rigidity an aesthetics. The belt holes in the B4 allow a full 5 6