Simple (and hopefully generic) clutch-disc centering tool for manual transmissions. There are existing designs out there for such tools, but they're all either specific to particular models, or need fiddly adjustments to fit your particular car's spline pattern. This design is Customizer-enabled and omits the splines entirely, as they are not strictly necessary for achieving alignment.

The default dimensions and overall form (including the lack of splines) are taken from a drawing given in the Peugeot 405 Haynes manual, and should be suitable for the BE1 and BE3 transmissions found in '80s-'90s Peugeot and Citroen models (205, 405, BX, Xantia etc.). However, if you can measure or look up the dimensions of your car's transmission input shaft, it should be easy to customize it for your own vehicle too.