Unless you always finish a pot / tub whenever you open it chances are you've ended up having to find a way to temporarily reseal it... or leave the original lid on and it ends up curling at the edges which effectively opens it up.
If you don't like leaving these tubs / pots open the common 'fixes' are a rubber band or aluminium foil neither of which are ideal as one flicks off easily and doesn't seal that well and the other is wasteful and not always easy to remove again.
Because there is a variety of shapes/sizes/curvatures of these pots / tubs it took a bit of trial and error to work out this system which will accommodate and work effectively on almost all of them.
The result is these clips which provide an effective solution that should fit most regular size pots / tubs of everything from sour cream to yogurt etc. However, a word of caution, while these work well in my country (New Zealand) you may need to scale the Z size if packaging dimensions are different in your country.
If you like this take time to check out my other designs!