This is a sample spool "blocker" designed to allow a much more organized sample spool arrangement.
4 will need to be printed to allow for 3 rows of sample spools.
You will also need (6) 2.5x10mm bolts, and accompanying nuts.
These are attached to the bottom of the container with double-sided foam tape.
These are designed for the Ziploc 26.5qt Weathershield container. https://www.amazon.com/Ziploc-WeatherShield-Quart-Storage-Clear/dp/B01M9CHXGX/ref=sr_1_13?keywords=ziploc+weathershield&qid=1577201230&s=home-garden&sr=1-13
The author remixed this model.