Designed specifically for use in Glock 17 (Gen4) and Glock 34 (Gen4) pistols, the LMS-G4-17 replaces Glock’s factory spring guide assembly with a high intensity red laser sighting system for advanced target acquisition. Easily user installed without the need for gunsmithing or special tools, the Guide Rod Laser is constructed with rugged, precision components including aircraft-grade aluminum and genuine Wolff springs.