Set of brass chassis inserts.  Total weight is right at 1/2oz with the hardware.  Just press the insert in and secure with 4-40 screw.   Compatibility: Prodigy SC   

1/2oz. brass chassis insert weight with GF6 engraved in it.   Compatibility: Five Seven Designs GF6

Carbon fiber chassis only.   Compatibility: Prodigy SC Mod

Paradigm chassis only.