I'm replacing a 30-year old large Tupperware container that I've used to hold flour. There are certain criteria that must be met and I'm having a hard time finding something that would work. I'd appreciate hearing what others use.

Criteria:

- air tight (I never had a problem with bugs or rancid flour with Tupperware)

- preferably lightweight and not breakable (metal?)

- large opening to be able to scoop flour

- Prefer square but will do round if necessary

Thanks!