These are perfect for your 3" trackball, with a nice even coat of black powder coating.  These carriage bolts include the nut and washer for mounting.

Perfect for Rampart reproduction or other trackball mounting.  Get rid of those rusty old bolts and replace them with a nice new set.

Please note these are high quality Nylok nuts.  All three pieces are finished in black for an amazing appearance above or under the control panel.