The design was made in NX 7.5.....

The carbon seat weighs only 4 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 in the B4 allow a full racing harness to be used
(a 5 or 6 point harness is recommended on an inclined seat).
The shoulder holes have been optimised to enable the use of a
Hans device. The shape is so comfortable covering is unnecessary making it ideal for open topped sports cars.