What documentation is required for a Non-O visa extension regarding bank balance evidence in Thailand?

For a Non-O visa extension in Thailand, you must provide proof of a bank balance exceeding THB 800,000 for more than 2 calendar months prior to your application. The required documents typically include a bank letter confirming the current balance, a comprehensive bank statement showing transactions since account opening or visa issuance, and an updated bank book with recent transactions, including a transaction from the application day. It's advisable to consult with your local immigration office for a detailed list of required documents, as requirements may vary by province.