The ZEV Technologies Competition Spring Kit contains an extra heavy trigger spring (heavier is better, as it helps you pull the trigger), a reduced power firing pin spring, and a reduced power firing pin safety spring. The result is the lightest and smoothest possible trigger pull for your Glock. When used in conjunction with the ZEV Technologies V3 Race Connector (153-418), the trigger pull weight is reduced down to 2 lbs total. DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.