I found the part I needed without difficulty and ordered it from an easily navigated website. It was delivered in a timely fashion.
Aerocool td/th4801 8 inch media
2 pieces
Td/th & ad/ah 4800/1 measurements: 20-3/16 x 8 x 22-3/4 each o/s we5ar wj9bl
Buy this part and as many parts as you like and pay only $9.99 shipping, within the Contiguous United States.