We recently purchased a home in suburban Philadelphia built in the 1940s. The house features original metal registers, which we had removed to have our duct work cleaned. We decided that we should replace the covers and upgrade to something new, clean and more practical/efficient at distributing the air. Unfortunately we discovered the duct openings are an odd 5" x 10". I have searched all ends of the Internet and supply stores looking for replacement register and return covers--with no luck. We need this discussion board's help! Thank you in advance!