Reflex sight or reflector sight is an optical device primarily used on firearms, cameras, and other aiming devices to provide quick and accurate aiming through a non-magnifying lens. The lens in use is a partially reflective spherical lens that acts as a concave mirror. It is kept in such a way that it reflects the light coming from the light source placed at the focus.

These optical devices work on the simple optical principle that anything at the focus of a lens or curved mirror (such as an illuminated reticle) will appear to be sitting in front of the viewer at infinity.

A red dot sight is a standard classification for a type of non-magnifying reflector (or reflex) sight for suitable firearms, and other devices that require aiming, that gives the user a point of aim in the form of an illuminated red dot. A standard design uses a red light-emitting diode (LED) at the focus of collimating optics which generates a dot-style illuminated reticle that stays in alignment with the weapon to which the sight is attached.

RRP S4E Innovations engineers two reflex sight PR 100 and PRM 25.

PRM 25 is an open-type red dot reflex sight that employs a light source at the off-axis focal point with a red dot size of 3 MOA (minute of angle). The spherical lens in use is coated with a special film that reflects only a specific wavelength, in our case, it only reflects a specific wavelength of 650 nm.

PR 100 is a tube-type red dot reflex sight, similar to PRM 25 this sight also has a red dot size of 3MOA (minute of angle) and has a similar coating that only reflects red light. A mesh is also provided which obstructs unwanted light that might cause unwanted reflection inside the tube.

MOA: A minute of angle (MOA), often abbreviated as "minute," is a unit of angular measurement mainly used in shooting. One MOA is equal to 1/60th of a degree or approximately 1.0472 arcminutes. 1 MOA is equal to 1.047 inches (~1 inch) at a distance of 100 yards.