You'll notice the coffin shaped window on top and the three windows per side, cuts weight and reduces recoil impulse. The deep serrations at both the front and rear of the slide create a more aggressive grip to insure a solid purchase during manipulations. The Hellbender slide provides durability and accuracy when it matters most. Manufactured in our state-of-the-art manufacturing facility from a single billet of 17-4 stainless steel to tighter tolerances than factory slides for increased consistency in barrel lockup for improved accuracy and performance. All ZEV slides have our patented optic cut that features threaded mounting posts machined into the slide. The increased surface area of these posts allows added engagement with the threads of the mounting screws while providing a more stable and secure optic mounting platform. With the deepest optic cut in the industry, the red dot sight sits low in the slide, allowing co-witness with standard height sights. ZEV slides weigh less than factory slides, therefore reduce reciprocating weight, which reduces fatigue and allows for faster shot follow-up placement. Technical Specs Machined from 17-4 Stainless steel billet Lowered ejection port to aid in ejection of brass Match grade, precision milled tolerances that are tighter than factory Improved accuracy and grouping performance upon installation DLC or PVD coatings offered have a Rockwell hardness rating above that of factory coatings RMR cover plate included Compatibility Glock 19 (1st - 3rd Gen)