[R-390] ADVICE ..... PSE, Cosmos linearity tool

[Larry H]

Hi Pete,  I assume you're referring to the bristo head screws for the linearity adjustment.  They are a .033" 4 spline bristo wrench.  Micro Tools makes one.  I got mine from Moody Tools on Amazon, part # 4-49-8130.  However, if the screws are not locked down tight, I prefer to use a # 4 flat jewelers screwdriver, .040" blade.  It  fits very nicely.
Remember, you can keep turning them clockwise until they fall down inside.  Then, they are a little difficult to recover.  There's a lot of info written about the Cosmos, if you have not read it yet.
Regards, Larry