Comments about AquaTech AquaTech Soft Collapsing Travel Lens Hood for 400mm f/2.8 & 600mm f/4 Lenses:

I purchased this sight unseen, thinking it would make a good substitute for travelling.
My only advice is see it before you buy it. It is HUGE. It is built like an brick outhouse.
Yep, it folds for travel, but it is astonishingly larger than the equivalent manufacturers lens hood. they say it is lighter than the manufacturer's hood, but that is probably only true if it was made out of 1/4 inch mild steel.
It attaches well to the lens, but, it is possible in the bush for it to be pushed off centre and so it can potentially vignette.
It is extremely well built and a great idea. Just its over engineered for practical work in the field.
So check it out before you buy. It may be just the thing you want, or too hard to use.