The Carbon/GRP B4 seat weighs only 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 comfortable inclined racing position. The belt holes have been optimised to enable the use of a Hans device. The belt holes in the B4 allow a full racing harness to be used (A 5 or 6 point is recommended on an inclined seat).