Machined from 8620 alloy steel with a QPQ black nitride finish Compatible with both For Glock and Colt AR-15 magazines For use with a standard AR-15 hammer Features removable weight for use with Law Tactical folding stock adapter Bolt carrier group compatible for use with both GLOCK and Colt style AR-15 magazines without any further modifications.table.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; }