Each of the Port A Box range has been developed with the mobile photographers in mine, taking up very little space in the gadget ba. If youre going for that studio softbox look in your lighting, but you only have an on-camera flash, what can you do? Interfit Strobies Portabox 22x 16cm for 580EXII/SB900 STR153 offers one great solution. This 22x 16cm (9x 6") softbox just slips easily onto the flashgun head & the rubberised sides grip the flash while the elasticated Velcro strap holds it firmly in place. The "window" is an opening that means that you can direct 80% of the flash power upwards to bounce off the ceiling & the other 20% through the softbox straight forward. The softbox can be used without interfering with AF functions, & it folds up in its included flat packed zip-up carry case when not in use. The High grade materials are identical to the Interfit Pro Range of Softboxes well known for providing a high quality light source.