9 1/2 inch diameter powder-coated steel. This Mr. Bird rain guard will help protect your cylinder feeders and seed treats from rain, snow, and all but the largest meteors. All bird seed needs to be kept dry to prevent mold and germination, so this rain guard will help keep your birds healthy and happily visiting the feeders. This will only deter the most uncoordinated squirrels, so look for the Mr. Bird squirrel guard to keep the squirrels away. Fully assembled, and no tools are needed.