Designed to allow you to run different weight springs with the added weight and strength of solid stainless steel.  This is not a captured guide rod and is for the 4.25" models only, in 9/40/357. Also works for the M&P Competitor.  Does not fit compact or .45 models.  Will not work with factory recoil springs.   Recommended for use with ISMI flat wire M&P springs, may not work with round wire springs.

.74 oz