this is just a box to keep the Cores, Oil and grease safely in one place. I still need to make the lid but thought I'd add this now. Just wanted to add that the core does fit but like when you fit it into the printer you need to press the lever so it goes in and the spring will hold it in place. with the UM3 toolbox lid, if you find it's not allowing to print then rotate in the Z axis 90 deg. Included is the lettering that you can add and have it with a contrasting colour.