The two white 'bricks' are the 12"radius sanding blocks I printed. STL files are readily available online. These are printed out of PETG so they're thermally stable and have a strip of 1200 and 800 grit paper for running up and down the fretboard to level things out once the big lumps are gone.
The block in the background (white on the bottom, blue on top) is a 3d printed clamping block or support block for the neck, the blue is printed from TPU (similar to what your clamp pads are made of)
In one of the pictures you can also see a bunch of red 'wings' on a white board, theyre the non marring plastic sockets printed to minimise the chances of me rounding bolts or stripping threads.