TRUGLO Brite-Site TFX, Sight, Fits Walther P99 and PPQ, Tritium/Fiber-Optic, Day/Night Sight, 24/7 Brightness TG-TG13WA1A Glowing bright both day and night" TFX(TM) sights are always ready. TFX(TM) takes their award-winning Tritium + Fiber-Optic technology even further with all the features their 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.