Bag organiser - where to buy?

[boredwithfootball]

Does anyone know where I could find a bag organiser that ties at the top?

I have a sort of drawstring thing in mind?

Basically I want something to make things in my open tote a bit more secure when I'm travelling on the tube. Any thoughts?

Amazon.

Wirecutter did a round up on this recently, I can't remember which they preferred, but they tested quite a few.