William H.C. Chang & Diana Shon Chang TTEE Chang Family Trust U/a DTD 10/23/2006 Sample Contracts

EXHIBIT A

Schedule 13d Amendment • January 16th, 2026 • William H.C. Chang & Diana Shon Chang TTEE Chang Family Trust U/a DTD 10/23/2006 • Electromedical & electrotherapeutic apparatus

• Contract Type
  Schedule 13d Amendment
• Filed
  January 16th, 2026
• Company
  William H.C. Chang & Diana Shon Chang TTEE Chang Family Trust U/a DTD 10/23/2006
• Industry
  Electromedical & electrotherapeutic apparatus

We, the undersigned, hereby express our agreement that the attached Schedule 13D, Amendment No. 12 is filed on behalf of each of us.