This is a captured guide rod that directly replaces your stock one. It is made from 303 ground and polished stainless steel. It includes a flat wound spring with your choice of 15#, 17#, 20# or 22# spring. You also pick from a polished stainless screw or black zinc screw.
Fits G17 G18 G22 G34 G35 G37 Gen 1-3, Does not fit Gen 4-5