The Profoto 2.3 x 5.0' RF-a Softbox is first and foremost a high quality light shaping tool that will soften the output of flash heads or continuous light sources up to 1,200W.
The "a" designation in RF-a is for asymmetric and it's what makes this softbox unique. Instead of placing the light head's mount in the center of the box, placement is in the upper third as oriented in portrait aspect. This is especially valuable to portrait and fashion photographers shooting full length who want to center the light source on the subject's face or faces without wasting the top half of the softbox's illumination on the ceiling while the lower half of the photo falls off into darkness. The scoop shape of the softbox ensures that this does not happen.
Separate purchase of a speedring is required for use.