Stephen,
I would have gotten the
Action Packer the lids snap lock on those and you can add a small snap link or padlock to keep them closed. I have one of the larger ones that drops down on my old S'Cargo trailer and attaches with a single ratchet strap. The Action Packers are as close to indestructible as I have ever seen in a storage box. I have some that are 10 years old that have spent their entire lives out of doors and are still in pretty decent shape...
Aaron