Vectrex DAC zero adjustment tool

I often have to fix Vectrexes. And I help my friends adjust their Vectrexes. One of the adjustments is to what we call the DAC zero adjustment pot. And usually I can not find a screwdriver that fits this odd shaped hole. I used to use a pen cap which would work, but was difficult. So now I've made my own tool for adjusting the DAC zero potentiometer.

Edit. I have now added a compact version. I actually like this version better. The compact version can be used from either direction.