The diaphragm of a moving coil loudspeaker.
"I recieved my shipment of CD transfers from my albums, plus the albums. Excellent job ! I also understand I miscalculated the shipping and that I owe you $ 11.00,and that you went ahead with the restoration work and sent me the albums and CDs anyway. I am putting together another shipment of source tapes (VHS, cassette and reel to reel) and ..."