Oval inline A/C and heater bulkhead fitting. The bulkhead fitting is great for running A/C and heater hoses through the firewall. The fittings on the bulkhead are standard A/C fittings: one #6 5/8″-18 and three #10 7/8″-14.
The bulkhead measures: 6-1/2″ x 1-5/8″