Section 10 ILCS 5/15-1 - Secure ballot boxes(a) Except in municipalities operating under Article 6 of this Act, the county board shall provide a sufficient number of ballot boxes, with secure locks and keys, at the expense of the county, for the several precincts and districts. There shall be an opening in the top of each box not larger than is sufficient to admit a single closed ballot to be inserted therein at one time, through which each ballot voted shall be put into the box.(b) The county board may provide ballot boxes not of a permanent type, not of wooden or metal construction, not requiring locks or keys, nor having doors or windows, if (1) such ballot boxes are so constructed as to be completely sealed and empty units upon delivery to the polling place, (2) they can be prepared for the inserting and depositing of ballots by the removal of a perforated section in the top of each such ballot box, which removal creates an open slot not larger than is sufficient to admit a single closed ballot to be inserted therein at one time and through which each ballot voted shall be put into the boxes, and (3) such ballot boxes contain a perforated door or flap on one side which can be unsealed and opened for removal of the ballots when voting has been completed. No ballot box authorized by this paragraph shall be used on more than one election day.