+2 extension works with the Taurus GX4 and its 13 round magazine Gx4 Mag Extension
Springfield Hellcat vs Taurus GX4: Magazine Capacity Comparison Taurus GX4 Magazine 9mm 11 rd. - Freedom Armory Taurus GX4 and GX4XL 18 Round Magazine for the 9mm. Grip is sized for either the STANDARD (smaller) or EXTENDED (larger) sized backstrap. ...