Vasculum. As a botanist I've possessed one for over fifty years. It's a rounded painted tin container, like a rectangular box, with a hinged opening down the whole of one side. Mine has a nice leather strap for carrying on the shoulder or round the neck. It for putting your collected botanical specimens in to keep them from getting squashed and drying out before you get home to study them. These days I can manage with just photographs now that I don't have to wait for days to get my film developed. I have an excellent hand lens that comes on excursions. My vasculum is somewhere in the house but it's so long since I've seen it that I've forgotten what colour it is.