This cartrage holds insert RNGN-32 in the correct geometry for surfacing Cast Iron and Aluminum with the RNGN Round, 2 sided inserts.  This cartridge uses CBN Diamond for Cast Iron, and PCD Diamond (Single Sided ) for Aluminum.  If the aluminum has ANY steel or cast inserts, you need to run our Bi-Metal Cartridge, whch has a speical CBN Diamond insert with custom special geometry.