Full spools of Filament that have been featured in prior months of Maker Box.
These spools vary from 0.5kg up to several kg and it will be noted in the drop down.
Printed Solid partners with makerbox.me.
Maker Box is a monthly service for 3D Printer operators who want to experiment with different materials. Each month, you will receive 4X new sample coils of different filament to test. If you like it, most of the manufacturers offer members a discount when they come back for a full spool.
You might love the samples that month. You might hate it. But, the benefit is that you'll get to find that out without having to plunk down the cash for a full spool of every new material you see.