Loofah, laffa, luffa, loofa, plantspons, sponskomkommer or gatwasser. Call it what you like, it grows from a plant, is completely natural and lasts me about 12 months before I retire it to kitchen duties, off to the compost heap after that. I like to pre-soak it with my shaving brush in a bowl of warm water for a minute or so before use. They work exceptionally well, and are not as scratchy as those nasty plastic roses available from your local supermarket, they come in all shapes and sizes, and some of them large enough to be cut into smaller sizes to get more bang for your buck.
I have experienced them to last longer in their natural shape so rather use as is before cutting it. Feel free to specify your ideal size in the 'notes to seller' space provided and we'll see if we can find one that fits the bill!