The Nanlite Fabric Grid for Asymmetrical Stripbank Softbox (18x43in) mounts to the front of the softbox to minimize light spill and add directionality by tightining the beam angle 50 degrees. Great for selectivly lighting subjects without loosing the soft quality of light produced by the softbox. Attaches easily and swiftly via touch fasteners and folds down flat for storage and transport.