ProFoto Disc Refl.
The Disc Reflector is designed to eliminate stray light without focusing or changing the light characteristics. Most photographers use it with an umbrella to keep light from spilling off the edges of the umbrella, but there are other uses too. For instance, the Disc Reflector’s small size and light weight makes it easy to bring along to an on-location shoot.
Max light output at 2 m with 2400Ws @ ISO100: f/64.1 (on ProHead).