This is an Oil Pump 4 Port Bi-Directional for a National vacuum challenger 607 pump. This part fits all National Vacuum 607 PRO Challenger Series vacuum pumps.
This is diagram part #53 on the 607 PRO fan cooled pump exploded view and diagram part #50 on the 607 PRO liquid cooled pump exploded view.
The National Vacuum Equipment Part Number is 123-000-004