These dividers seperate a deep sqare Milwaukee Packout container across corner to corner. Very helpful for getting twice as many items into your packout. Works well for lots of different items like screws, anchors, nuts and bolts, connectors, etc. There is still enough room on each side to get your fingers in to pick up whats inside. I use these to seperate various lengths of concrete screws in one packout and to seperate different coaxial and BNC connectors and adapters in another packout. The piece is modelled to match the contours of the container exactly and to have the lid touch the top of it when the pack out is closed so that no parts will slip underneath. They have a slightly tight fit so they stay in place and don't pop up and allow your parts to mix when you have the packout opened.

For the larger rectangular bins, check out my other design: https://www.thingiverse.com/thing:6427721