Alignment pins for precision without measuring Removable drill guide blocks (1/4-in and 3/8-in) with lifetime drill guide warranty. Hardened steel drill guides for perfectly straight dowel holes Designed for use with trigger-style clamps for improved accuracy and stability Dowel alignment groove ensures consistent hole placement on both pieces. Reference lines make it easy to center on workpiece marks Corner joint alignment pin slots provide additional options for drilling dowel holes, Manufacturer: Kreg