This is a XS Sights Sight known as the F8, model CZ-F009S-5.
Shoot better day and night. XS F8 night sights increase front sight focus by using a large" high-contrast front sight for fast sight acquisition. The wide notch rear sight easily aligns with the front sight and increases front sight visibility. XS F8 night sights give you the best notch and post solution for fast sight acquisition in all lighting conditions.
Features:
Tritium front with orange ring
Tritium rear
Easily install by hand or sight pusher tool
