TRUGLO Brite-Site TFX Sight, Night Sight, Low, Fits Glock 17/17L/19/22/23, 24/7 Brightness TG-TG13GL1A Glowing bright both day and night" TFX(TM) sights are always ready. TFX(TM) takes our award-winning Tritium + Fiber-Optic technology even further with all the features our customers requested: compact snag-free design" longer sight radius" and amazingly durable construction built to handle just about anything. Illuminating elements are encased inside a virtually indestructible chemical and shock-resistant capsule and the CNC-machined steel is protected with a rust-proof FORTRESS FINISH(TM). There is even a highly visible white ring surrounding the front fiber to make it even more visible" encouraging the eye to rapidly focus on the front sight for a fast and accurate sight picture. TFX(TM) sights will amaze even the most discriminant shooters.