This is a Truglo Sight known as the Brite-Site, model TG13CZ1PC.
TruGlo Brite-Site TFX Pro For CZ 75 Series Green Rear Green With Orange Focus Lock Front Sight-The TFX CZ 75 Set Pro ORN Handgun Sight provides a longer sight radius for tighter groupings. The aiming elements are encased inside a virtually indestructible chemical and shock resistant capsule. All of the CNC-machined steel is protected with a rust proof Fortress Finish. There is even a highly visible white ring surrounding the front fiber to make it even more visible.
Features:
Green with orange ring front
Green rear
Fully protected TFO technology encapsulated in a virtually indestructible configuration
Utilizes quality Swiss tritium for maximum brightness
Angled rear sight edge for emergency one-hand operation