Safe Deposit Boxes At Security National Bank of South Dakota, we are proud to offer Safe Deposit Boxes to our customers. Our vault is equipped with 462 boxes that are sized 3x10, 5x10 and 10x10, each with a length of 22 inches. Four 20x26 combination safes complement our large box selection for customers that prefer the safety of a bank vault. For added convenience, we can directly debit your account for the annual fee.