Material: Nylon This is a mesh bag from Takakuracho Coffee. I've used it a few times, but there are no noticeable stains. I washed it and stored it in a dark place. It can stand on its own and is sturdy. It has a button and an inner pocket inside. I will fold it up small for shipping. I may change the shipping method between Rakuraku and Yuyu at the time of shipment.