Simple protection
I have UV filters that I keep on my camera's lenses when I am not using the graduated ND filters. That means when I am using the grad ND filters that I need a home for the simple filters. I've had a filter wallet for a while, one that is supposed to fit 3 filters. It does, but I've never been very happy with it - things just feel too tight.
I recently discovered that OP/TECH USA has something they call a Filter Pack that is a simple neoprene sleeve that takes two filters, one on each side. At the same time I ordered my Filter Packs (from B&H, where else?!?), I discovered some neoprene pouches from Zing Designs. Filter Packs fit into pouches, perfect!
Sometimes very simple things make me happy...