Holosun 403R is a red dot sight of the Paralow series.
The letter 'R' indicates that the device features a rotary switch for setting the illumination intensity instead of the two buttons found on most Holosun red dot sights. The switch is located next to the battery compartment, on the side of the device.
Even though this device doesn’t have ‘U’ in its name, it comes with shrouded turrets.
‘RD’ indicates that this red dot sight features red illumination.
Main features of 403R red dot optic
2 MOA dot
red and gold illumination
comes with a low mount and a high mount for a lower third co-witness on standard AR platforms
red dot optic features shrouded turrets
rotary switch instead of buttons for setting the illumination intensity
same mounting platform as Aimpoint Micro devices
12 illumination intensity levels, 2 of them are NVD compatible
holosun 403r parallax: micro optical sight is parallax free
up to 100.000 hours of battery life
the battery compartment is on the right side of the device under a round shaped cover