ArmaLaser GTO GREEN Touch-Activated Laser Sight for Guns & Pistols with Picatinny Rails (cross-notched rails). FITS: Glock 17 19 20 21 22 23 31 32 34 35 (plus the 48 and any other model that has rail with a cross-notch). There’s never been anything like the GTO. GTO fits onto almost any Picatinny Rail. GTO’s brilliance comes from over 75 custom-fit FLXs which activate the laser just by gripping your pistol. Laser Activates by Normally Gripping Your Pistol. No reaching for a switch. No awkward button on the grip. FLX allows GTO to turn on instantly. Patent 9,328,994 Additional Patents Pending. Custom-Fit for your pistol model. Made from the same material as Polymer pistols. FLX’S are made from an Ultra-thin, Ultra-strong NASA-used Polymer with 3M adhesive backing. Will not harm pistol finish, cleaning solvent-resitant. Super strong and stays put. Made with Dupont Zytel. Can be used without a FLX. Laser can also be activated by touching GTO sides. Activate laser by touching either side contact with extended trigger finger. Don’t install the included FLX if you prefer this activation method. Easy to live with. Convenient battery door means never needing to re-adjust laser after baterry changes. Easy to control over windage and elevation. Master kill switch for iron-sights practice. To be defective in either parts or labor.