Indoors and out, ideas come to mind. What happens if we roll a marble or a wooden ball in the channel? Make a target for bean bag toss? Will the parts float? Let’s sink ’em? Can we mold sand or snow? Throw the rings like flying saucers? The ideas are endless. The learning opportunities priceless. Outside dimension measures 9 3/4″ diameter. Made of high quality, food grade HD-PE, Nello is recyclable.