An Edge Mask is an accessory for Softboxes. It is like an additional diffuser which you can easily mount on the front of the Softbox thanks to the Velcro. The inner part of the Edge Mask is a completely dark rectangle where no light is passing. The light only shines through the edges creating a frame of light. The purpose of the Edge Mask is to create a contour light around your subject. To achieve this nice effect, you place the Softbox with the Edge Mask exactly behind your subject.
