Experienced shooters realize plastic guide rods can chip, crack or break resulting in feeding or ejection failures and guide rod flex can contribute to accuracy problems. The Lone Wolf Guide Rod Assembly addresses all of these issues and will provide you a lifetime of reliable service. Specifications for Lone Wolf Arms Complete Glock Guide Rod Assembly: Manufacturer: Lone Wolf Arms Color: Silver Gun Make: Glock Model Generation: 3, 2, 1 Condition: New Features of Lone Wolf Arms Complete Glock Guide Rod Assembly: Complete drop in unit for Gen 1-3 Glocks Precision CNC machined to accept a removable 3/32 Allen head tip Models 17/22 and 20/21 feature LWD's own 17lb flat wound recoil spring Models 19/23 use a LWD 18lb flat wound recoil spring Spring weight calibrated to factory weights. 75% heavier compared to OEM part. (1.4oz vs .8 oz) These combined features make the Lone Wolf Arms Guide Rod Assembly the most durable, longest lasting system available today. We recommend spring changes every 3,000 rounds for 40/10/357 and every 5,000 rounds for 9/45 Package Contents: Lone Wolf Arms Complete Glock Guide Rod Assembly