Agency Arms Glock 17 Gen4 Magazine Well for No Back Straps Black. This minimizes the possibility of dropping the magazine during a draw. It also allows confident that the magazine will not inadvertently slide off the end of the mag-well during normal use. The magazine-well insert is installed through these areas and then tightened down with the set screw. Due to the extremely low profile design of the mag-well the magazine cannot be inserted until the end of the magazine inserts. Because this is a set screw item installation is necessary. Specifications for Agency Arms Glock Magazine Well for No Back Straps: Manufacturer: Agency Arms Color: Black Package Contents: Agency Arms Glock Magazine Well for No Back Straps Agency Arms AGEMW-G17G4-NBS-B: Glock 17 Gen4 Magazine Well for No Back Straps Black