Filament Rack Extender Attachment

If you bought the same racks as me from amazon (link below) and you want to stack them, then you will need this attachment to extend their hight to be able to store normal sized 1K rolls in the middle section. Amazon.com: Desktop 3D Printer Filament Storage Rack - Tabletop 2-Tier Stackable Organizer for Filament Spools, Holds 6 Spools per Layer, Expandable to 4 Layers for PLA/ABS/TPU Filament (2-Tier) : Industrial & Scientific