This is a Spring Wave Wire 3.5″ Dia for a National vacuum challenger 607 pump. This part fits all National Vacuum 607 PRO Challenger Series vacuum pumps.
This is diagram part #15 on the 607 PRO fan cooled pump exploded view and diagram part #17 on the 607 PRO liquid cooled pump exploded view.
The National Vacuum Equipment Part Number is 120-045-001