Gridfinity 3/8" Drive extension holder

This is a set of gridfinity blocks to hold 3/8 drive extensions flat in a toolbox drawer. I have a lot of these, so you might not need both blocks. There is a 3x5 block and a 2x5 block. The photo in the green outline out of the blue material is this model. 1x 9", 5x 3", 5x 6", 4x 1", 1x U joint, space for some adaptors to go up to ½ or down to ¼.

Enjoy

Edit 4/29/2026:  I've added the step files of 3 additional blocks that are  split like the ¼ extensions that I have.