This sight set is for Glock pistols and does not require modifications to the slide. It is a Heinie LEDGE Straight Eight design with a .156 wide and .120 deep notch. This sight design is great for one-handed clearance drills. The "Straight Eight" configuration is one tritium dot in the front and one tritium dot in the rear that aligns vertically for fast acquisition in low-light situations. FeaturesDesigned for easy one-hand cycles QWIK notch width of .156" Notch depth of .120"Easy to see Tritium inserts during low light environments Front & rear sight serrations help eliminate light glare 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.