A4 Stainless Steel is not a material anaerobic threadlockers and thread sealants are supplied in. Anaerobic Threadlockers and Thread Sealants are specified by inside diameter, and this combination does not describe a part that exists.
The materials that do apply are: NBR (Nitrile), FKM (Viton®-type), EPDM, Silicone (VMQ), PTFE.

