Extension holders for 1/4", 3/8" and 1/2" drive extensions.  Why are these different?  Well, the 1/4" and 3/8" take up minimal space because they are half grids wide.  I also didn't waste any space for labels, keeping everything as compact as possible.

While all holders have 6mmx2mm press fit magnet holes, the half-width holder will probably need to be glued.  I recommend magnets especially for the half-width holders to help keep them in place.  I had a short 1/2" extension that was able to stand upright in my toolbox, so I included that holder as well.  All holders are 3U tall to match my other accessories.

Modeled with Craftsman extensions, but I am sure other brands will fit.  If not, I can easily generate an alternate size if you need one.  1/2" holders were tested with Pittsburgh (Harbor Freight) impact extensions and Craftsman non-impact extensions.

These are part of ratchet organization system:

Ratchet Holders: [https://makerworld.com/en/models/1461015-gridfinity-universal-ratchet-holders-with-magnets](https://makerworld.com/en/models/1461015-gridfinity-universal-ratchet-holders-with-magnets)

(this model) Extension Holders: [https://makerworld.com/en/models/1460976-gridfinity-ratchet-extension-holders](https://makerworld.com/en/models/1460976-gridfinity-ratchet-extension-holders)

Harbor Freight Wobble Extension Holders: [https://makerworld.com/en/models/1460924-harbor-freight-wobble-extension-holder-gridfinity](https://makerworld.com/en/models/1460924-harbor-freight-wobble-extension-holder-gridfinity)

Blanking Plates with Customizable Labels: [https://makerworld.com/en/models/1457744-customizable-gridfinity-blanking-plates-and-labels](https://makerworld.com/en/models/1457744-customizable-gridfinity-blanking-plates-and-labels)

Happy Organizing!

I buy these magnets on Amazon.