Interfit's Strobie Portabox W/Window for Canon 580EX11/Nikon SB900 (9x6") offers one great solution. This 9 x 6" (22 x 16 cm) softbox just slips easily onto the flash (compatible with the Canon 580EX11 and Nikon SB900 flashes) and is held in place by a touch-tab strap. The "window" is an opening that allows you to direct 80% of the flash power upwards to bounce off the ceiling and the other 20% through the softbox straight forward. The softbox can be used without interfering with AF functions, and it folds up in its included flat packed zip-up carry case when not in use. Made from the same high grade materials used for the Interfit Pro range of softboxes.
Reviewed by 2 customers
Use for softening the flash for portraits. Works well for its intended use. Not a large soft box though. It is portable and easy to attach.
If you need a little soft box for your speedlite this will fill the bill. Price is right and folds up nicely in the pouch. Works well on beach shoots where big soft boxes become a sail.