The Bowens Standard Reflector Barndoor Set has been designed for use with the Standard Reflector BW-6710 (not included) to flag off light to control the spread precisely without changing the light characteristics.
The 4 barndoors can be adjusted individually and the entire tool can be rotated 360° on the flash head, allowing you to control and shape light in an almost infinite number of ways.
This allows you to create an asymmetric light spread.