A sealed ballot box used under this subchapter must be equipped with a lock to prevent opening the box without a key and designed and constructed so that:
(1) the ballots can be deposited and delivered without damage that will render them unfit for processing in automatic tabulating equipment;
(2) the box can be sealed to detect any unauthorized opening of the box; and
(3) the slot used by voters to deposit ballots can be sealed to prevent any unauthorized deposit in the box.