A cheap, full metal sidearm that runs well. The Dr. Black 60 degree bucking is softer than stock and gives more hop with 0.25g BBs. The KJW flow valve is made for KJW M9 magazines and is the part to replace when a mag starts leaking. Example build by LoadoutLab. Every part is listed by its shop as made for this gun. Photo: "KJW Beretta M9 GBB.jpg" by madhood, public domain, via Wikimedia Commons (https://commons.wikimedia.org/wiki/File:KJW_Beretta_M9_GBB.jpg). The photo shows this gun model; the parts list is a suggested setup.