Specifications and FeaturesAmerican Tactical ATIBG37CONVConverts GLOCK 37 Models Chambered in .45 GAP into shooting .40 S&WPrecision Engineered CNC Cut 416 R Stainless Steel BarrelBroach Cut/Finished HonedDrop-In Fit, No Gunsmithing Required1:10" Right Hand Twist RateCompatible with Lead BulletsMatch Grade AccuracyMade in the USAStainless Steel Barrel FinishFits: GLOCK 37 ModelsIncludes:BarrelMagazine FollowerExtractor