The ZEV Technologies Starter Spring Kit features the ZEV Pro Connector, 2lb Striker Spring, FPS Spring, and Trigger Spring. The Pro Connector has been engineered to provide users with a consistent, positive reset and a reduction in trigger pull weight without sacrificing the reliability or safety of your pistol. Whether used in conjunction with a ZEV trigger or with your stock Glock trigger, the PRO connector will provide a noticeable increase in performance and is ready to drop-in and use straight from ZEV, no fitting or polishing required. 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.