6x1x5 gridfinity bin for 3/8" extensions. fits two 3" and two 6". should fit most brands. I have a mixture of Tekton and Mastercrapt. Push down on the ratchet side of the extension to tilt and remove.

Gridfinity is a free, open-source storage system that uses a matrix of squares to organize tools and spare parts. It's designed to help users work more efficiently by making it easy to move and rearrange items.