I have purchased a second hand tool box for the new ute saving me having to put a tray on it.
It has compression locks. How secure are these and can anyone give me an alternative to making it reasonably secure.

It will carry quite a bit of equipment as this car will be towing the trailer for commercial work approx 3 days per week.

It will be parked securely overnight but want to take the extra precaution.

I got the box at a good price - would have been probably 2.5 times what I paid to get one made up like this. see attached>>tool box.JPG