since it 400 quite narrow for existing filters and filter adapter was in my Tamrac Explorer, had to find a solution.
A larger bag was eliminated for reasons of cost and greater extent. Fortunately Tamrac MAS offers the possibility to attach accessory system of bags, which also support MAS. The filter bag is easy to mount and is securely attached. The build quality is good, the Velcro requires a relatively large amount of force - an accidental fall of filters is not possible. I am therefore very pleased with this product.
Alternatively, a smaller filter bag by SAS System used (mounting on the shoulder): Tamrac SAS Compact Filter Case MXS5363 black