The black Glass Limo Backpack from ThinkTank is specially designed to hold long lenses. Specifically, it's meant to accommodate a 600mm f/4 or 500mm f/4 without a body attached or 400mm f/2.8 with pro body attached. The backpack has a padded collar for stabilizing 300 mm and similar size lenses. However, when fitting larger lenses, you must remove the padded collar, or the larger lenses won't fit properly. A versatile backpack, it can be reconfigured to hold a standard DSLR and about 5-8 lenses. The interior movable touch fastened dividers allow you to customize the pack to suit your gear needs. In order to hold the long lenses in place, the pack comes with specially designed touch fastened collars that secure the lenses in place.