Made from hardened steelDirect replacement OEM Sig PartPrecisely machined with skeletonized cutout - lightening the trigger weightX-Series Version Skeletonized trigger compatible with the following models:P320X5X Series80% Sig Build InsertFlat trigger for 90 degree breaking pointSkeletonized Flat X Series Trigger compatible with the following calibers:9mm.40 S&W.357 SIG.45 ACPFinished in BlackAny machined area is put through our in-house blueing process to maintain corrosion and wear resistanceThis is the non-upgraded skeleton trigger, it features a smaller ledge, it's Sigs' regular flat trigger - you can view the upgraded Flat Sig Trigger by clicking hereAlso available is the Factory OEM Sig Flat trigger - No machined skeletonized cutoutCheck out our video showing the trigger by clicking here