Found under the following brands:
Master Tool Repair
New style filter assembly has 3/8" threads. Includes new style air filter, head and o-ring. See Specs tab for more info!
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 to predrill 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 your head looks like this below with 2 holes on the SAME side of the head. This is NLA