Found under the following brands:
Master Tool Repair
Pump head 3/8" FPT filter port and 3/8" outlet port
This item fits the following models
This head has 3/8" FPT threaded ports on both sides. If your head has a 3/8" port 90° from the air filter, you will need to take a 9/16" drill bit, predrill and then a 3/8" pipe tap (if your head has 3/8" outlet) to tap the hole for your unit. Simply take a 3/8" plug and plug up the unused hole.
Do NOT order this if you head looks like this below with 2 holes on the SAME side of the head. This is NLA.