BudsGunShop.com - threaded barrel

Jacqulyn, thread pitch is metric 8x.75 and yes, it needs the following ½x28 Walther Adapter : keepshooting.com/walther-p22-thread-adapter.html

Walther emailed me back, their response to "does this require an adapter?"-----------
"Yes, it does. Please see the link below:
thesilencerstore.com/product-p/ad-22-001a.htm
"------------------
Thank you,
Marcus Mirus
Gun Tech
Walther Arms, Inc.
479-242-8500 ext. 507
7700 Chad Colley Blvd, Fort Smith, AR 72916

Walther website shows an adapter that's threaded ½x28 TPI but ots listed as "discontinued" they make no mention of an adapter needed on any of their threaded barrel models but the also don't list the the thread count. I emailed Walther and asked them for some clarification.
You can contact Walther here
https://waltherarms.com/contact-us/
---------------
CUSTOMER SUPPORT
479-242-8500 EXT 507
customerservice@waltherarms.com-------------------
Or I will post the answer when they return my inquiry.