This is a Gridfinity insert (1x6) for the LTT screwdriver. Compared to the original model, there is a bit of the tip removed from the Gridfinity shell, elongating the shaft cut-out, so that the driver still fits in with a bit installed.

Also there is an “Easily Removeable” profile which has a finger cutout in the back and a cutout below the shaft so that pressing down on the shaft levers the back handle up for easier removal.