Genuine factory Glock 23 .40 S&W 10-Round magazines. Polyethylene body with a steel liner. Compatible with the reversible mag release on Gen-4 guns as well as earlier Generations 1-3. Fits flush on the compact frame of the G23 and, as with all Glock mags, they will still function in the smaller framed sub-compact G27. Will not fit the full size G22 or G35.