Designed specifically for use in Glock 20/20SF/21/21SF Gen-1-3 pistols. The LMS-G4-1151G 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.
Specifications:

Wavelength	532 nm
Dot Size	.31" @ 7 yds
Power	5mW
Range	20yds Day/300yds Night
Weight	.8 oz
Battery
Laser Color	Green
Firearm Fit	Glock 20/21 FG/R/20SF/21SF (Gen 1-3)
Reticle
Power Switch	On/Off
Adjustments	No
Finish	Black
Mount Type	Guide Rod