Glock Recoil Spring Assembly Dual 9mm (G19 Gen5, G19X, G45, G45 MOS) Marked 1-7. This steel and polymer dual recoil spring assembly will fit Glock G19 Gen 5, G19X, G45 & G45 MOS pistols chambered in 9mm. This assembly is marked 1-7 on the end. This is a factory original Glock Part. It is made to the same high standards in material and workmanship as the parts that originally came in your Glock firearm.