I created a divider to modify the SnapLock Storage Box to create a utensil carrier for camping.  
This is for the divider insert only with personal use in mind, since the box does not allow remixes.  
The divider fits the 240x180x50 box, but can easily be cut to fit other sizes since the chamfer is the same across all of the boxes.
 

To use:

• add the STL to the plate
• merge the objects
• open the object view to see the assembly
• move the divider to the desired location

Snaplock Storage Box source:
https://makerworld.com/en/models/213420-snaplock-storage-boxes#profileId-239408