hi all, can someone tell me what the parts under the fake coals, that look like the casleations on top of a castle wall are called ? they look as though they spread the gas and flame around the coals and appear to be made of the same material as the coals. also where can I buy them from, do they have to come from the manufacturer, because they are specific to the fire or can I buy them and replacement coals somewhere like ebay ? thanks, Ian.