4L US Really Useful Box Divider Insert

I love my Really Useful Boxes but wanted more use out of them, so I designed this box you can use to further divide your 4L US box into 4 compartments. This will also work in a 9L US box, but the height is meant for a 4L - I'm working on other boxes for both 4L & 9L US boxes, too. There is wiggle room on each side so it's easier to take them in/out; feel free to adjust the ratios a little if you'd rather have a tighter fit. Please note - this is designed for the US VERSION ONLY. Again, 4L or 9L US VERSION *ONLY* - boxes sold in other parts of the world have different dimensions.