These are the exact type knobs used on Intellijel modules but in white. (Shapeshifter, Metropolis, Atlantis, SpringRay etc.)
They are manufactured by Sifam (in the US distributed by Selco).
These are available in 6mm D-Shaft and Reverse D-Shaft (see image below for guidance).
The Cap comes separate from the pot body so the orientation of the cap pointer to the D-shaft can be set at any angle (e.g. you can choose either zero degrees or 180 degrees, which are both typical). The body and cap colours are an identical match to Intellijel colours.
These knobs are not an Intellijel product and are not sourced via Intellijel.