This is a Crimson Trace Corporation Red Dot known as the CTS, model CTS-1100.
The CTS-1100 Electronic Sight is an Illuminated 3.5x Battlesight for rifles and carbines. Featuring 3.5x magnification and a fully illuminated hybrid BDC (Bullet Drop Compensator) reticle" the CTS-1100 provides a superior field of view for engaging targets at close" mid-range and long distances" elevating your long gun's performance instantly. Installed in seconds by utilizing an integrated M1913 Picatinny rail mount" the CTS-1100 boasts a rugged design for years of use.
Features:
3.5x magnification for superior field of view
Fully illuminated, hybrid BDC reticle
Integrated M1913 Picatinny mount
Shock, impact, fog and vibration resistant design