For agencies who require advanced corrosion protection, these replacement screws are made of 18-8 stainless steel with black oxide finish.  Rated at 70,000 psi tensile strength, they are softer than the steel screws that come with the Rukh but still plenty of hold-strength for the most rugged use.  However repeated mounting / dismounting will ultimately weaken the threads, and should be replaced after approximately 20 dismount/remounts.  Also the torque driver is required.
Full disclosure: you can purchase the same screws for significant less directly from a hardware store.  A box of 50 is less than $10 (plus shipping) at McMaster Carr, parts# 96006A618.  You are really paying for our labor to repackage them if you buy from us, and the convenient of one-stop-shop.