The Sightseer lens pouch comes with:
-1 false bottom divider, you can stash memory cards or batteries under this or even stack lenses by using it as a divider in the single pouch.
The Medium Lens Pouch is designed for your midrange zooms and fatter primes such as the 105 f/1.4. It can also carry the newer 70-200 f/2.8 lenses albeit very tight.
The Medium Wide pouch is also a great small bag for your smaller mirrorless cameras such as the Leica M.
These pouches and accessories (sold separately) can be attached to the Sightseer Lens Bag via 2 rows of thick, velcro backed Leather straps and also 2 side straps. This idea is derived from the standard for military use modular systems.