I assembled this from 6 in corrugated pvc drain piping. It's the only part I couldn't find a suitable piece to just purchase. I thought the standard 6 in pvc too heavy and large. So I bought some sections about 4-5 in long, drilled 7/32 in holes in them, used 19 ga (1 mm) galvanized steel wire to fasten them together (they were cut vertically) and pvc glue to hold them tight in a stack. Rough, but I hope functional.