The Honl Photo Traveller8 Softbox can be used to create beautiful soft light on the go. The compact 11 x 9" softbox provides a pleasing circular catchlight in your subject's eyes. It is extremely easy to setup and attach to your shoe-mount flash unit. Just use the included speed strap. For traveling the softbox folds flat to tuck into your camera bag, and weighs less than 4 ounces.
I use the Traveller8 primarily for on-location work, but only for off-camera flash (when I have an assistant). It just doesn't work well for on-camera flash. It extends beyond the tip of my lens (24-70mm) and droops such that it is slightly visible through the lens. The velcro keeps the diffuser from slipping off the flash, but not from drooping. I love the light it generates, however am still looking for another on-camera diffuser for those situations in which I'm continually on-the-go or don't have an assistant. I also use the Traveller8 for in the studio for hair lighting -- it's a great small lightweight addition to my studio lighting setup.
Sturdy, does it's job, works with the Honl system flawlessly, it's just the right size (even w/ flash on camera and pointed straight out doesn't get in the way of the lens, not even on a 16-35), I can just toss it in the dufflebag and then toss 3 light stands on top of it and it won't even care. Cons? Pricy!