It's the Pro M Frame case. Since it had to be larger to accomodate the non-folding stems, they used the extra space to add some other spare lens holders.
From my memory, I thought it held another just before or behind the Attached lens, but seems not. You could always put one in a microbag and slide it in, since that front lens slit is wider.
Another, newer version of the Soft Vault Box is now in O-Stores/Vaults. I think it is the same one that came with the Radar bundles from the past couple years. The foam cutouts hold one complete frame/lens combo, three extra lenses, and a hydrophobic kit.