Each of the PortABox range has been developed with the mobile photographers in mine, taking up very little space in the gadget bag, each PortABox is supplied with a zip up flat packed carry case. The High grade materials are identical to the Interfit Pro Range of Softboxes well known for providing a high quality light source. The 30 x 20 cm softbox can be used directly on camera without affecting the AF functions of the flashgun(on most current flashguns). To fit the PortAbox simply place it over the flashgun and wrap around the Velcro strap tighten as required. The STR150 Strobies PortAbox 30cm x 20cm ( 12" x 8") is designed for use with the Canon 580EX and Nikon SB600/SB800 flash units.