TRUGLO TFX Sight, Day/Night Sight Set For FN FNX, Front Sight Color Green W/ White Focus Lock Ring, Rear Sight Color Green, Green Tritium TG-TG13FN1A Glowing bright both day and night" TFX sights are always ready. TFX 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-resistant FORTRESS FINISH.