This is a Left Hand model, it will work with Left Hand AR15 Upper receivers onlyFor 7.62x39, 9x39, or similar, designed to run both steel and brass cased ammoMachined in house and assembled using only the finest steels and components.KAK Industry takes pride in producing some of the finest AR15 bolt carrier groups available, made 100% in house at our MO facility using the latest in robotics manufacturing techCarrier- machined from aircraft/bearing quality 8620 steel, heat treated, ground to perfection, and nitride treated by H&M BlackNitride(TM)Profile- M16 full auto profile carrier with correct sear trip placementBolt- Machined from aircraft/bearing quality 9310 steel, heat treated properly, precision ground, and Nitride finished, standard .125 bolt face depth, MPI TestedFiring pin- Machined to the mil-spec print from 8740, precision ground, properly heat treated, and chrome platedCam Pin- Nitride treatedExtractor- Machined enhanced billet extractor - phosphate coatedEjector- S7 tool steel ejector and extractor retaining pinGas Key- 4130 steel, nitride treated, precision staked using our hydraulic staking machineFor 7.62x39, 9x39, or similar, designed to run both steel and brass cased ammo