Filament rack clip

This is a clip for holding together https://makerworld.com/en/models/909081-filament-spool-roll-storage-rack-with-label#profileId-869634It will hold together two of these shelves horizontally, increasing the stability.It is a very tight fit, and needs to be jiggled in place while the rack is built up, it is almost impossible to place them after the fact.The little arrow is to be placed between the two legs in the gap between them.