The ProMag Drum Magazine for the Glock 42 features a magazine body constructed from a proprietary DuPont Zytel based polymer. The follower is injection molded and the magazine spring formed from heat treated stainless steel wire. FeaturesMagazine body constructed of a proprietary DuPont Zytel based polymerInjection molded magazine followerMagazine spring formed from heat treated stainless steelMagazine upper tower has full length steel internal insert stamped and welded like the factory magazine DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.