Renaissance 18" diameter round Aluminum Cast Grill, outside dimension is approximately 20". Thickness is 1/4". Available three different ways: with a damper for air supply control; with a mesh screen; or plain with neither. Most heat registers will ship in 4-6 weeks but some sizes and finishes may take longer. Please call for availability and lead time on specific sizes and finishes. Available in three painted finishes, click on image below to see finish options.