This card case is designed to hold 4 cards, it is simple with no lining to ensure that it is totally biodegradable at end of life. BioD is a special material designed to be broken down by microbes and biodegradable within 180 days, but only in compostable conditions. So it will be fine in your bag or pocket but when you have finished with it, there is no need to send it to landfill, just pop it in your compost heap.