GearWrench 388765N 12mm x 1.50 NF Hex Die The GearWrench 388765N 12mm x 1.50 NF Hex Die is manufactured from carbon steel for maximum durability. Made for cleaning up damaged threads, the GearWrench 388765N 12mm x 1.50 NF Hex Die features clear laser-etched markings for easy identification.