Maxim Defense Industries Gen 7 SCW Pistol System, Standard Kit, Buffer Tube Complete Assembly, Anodized Finish, Black, Includes - Housing, Tube, Standard Buffer, Spring, BCG MXM-48549 The SCW Pistol System by Maxim Defense is your choice for simplicity and ultimate compactness for your AR-15 pistol. This system features a Gen 7 style housing" and SCW length buffer tube. The SCW system requires the use of the proprietary bolt carrier group" buffer" and spring - the same combination used in Maxim's tried-and-true SCW stock. The SCW Pistol System is compatible with any MIL-SPEC lower receiver and it does not accept a stabilizing system. If you already own a SCW system" you only need the housing to make this conversion. Be sure to select the full kit if you are starting from scratch. When you want minimal length added to your AR pistol" it doesn't get any better than the SCW Pistol System.