Glass Weather Dome - 11" transparent glass awning deflects water and debris away from the birds and their dish. Detachable Metal Holder - Easily slide the seed cylinder over the metal rod for simple installation and maintenance. Size Compatibility - Works with up to three seed stackable seed cylinders or seed balls up to 5" in height. Drainage - Subtle rubber gasket inserted between the metal and the glass allows drainage keeping the seeds fresh. Waste Prevention - Cylinder feeders allow birds to pick the food they eat limiting the amount of food spilled or wasted.