This is an Arri 4 Leaf Barndoor Set for the 2Kw Studio (NOT Compact) 5K Compact, 2.5K HMI, and Arrisun 12. Barndoors attach to the front of a light and are used to restrict light from areas of a set. They have either four or eight leaves that can be adjusted. Arri barndoors are heat resistant and rotatable.