LaserMax Hi-Brite Model LMS-G4-19G Green Laser, Fits Glock 19 Gen 4, Guide Rod Laser LMS-G4-19G Designed specifically for use in Glock 19 (Gen4) pistols" the LMS-G4-19G replaces Glock's factory spring guide assembly with a high intensity green 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.