Using patented, state-of-the-art holographic optics technology similar to that used in the heads-up displays in advanced fighter aircraft, the HWS was designed to provide the operator with improved shooting performance by achieving a more rapid reticle-to-target acquisition. Holography provides a number of advantages for a small-arms sight. The use of holography allows a reticle image to be created in any light pattern, geometric shape, or size. The reticle can be produced in either two-dimensional or three-dimensional form. With holography, a parallax free reticle image is created and projected out to the target plane, allowing the operator to focus on the target. The reticle image is of uniform brightness and distortion free. The sight remains fully operational with point of aim/impact maintained when the sight is obstructed by mud, rain, or snow, or even if the window is shattered. Seeing the target through any portion of the window enables the operator to obtain a reticle-to-target lock-on. The speed of reticle/target acquisition is among the fastest of any optical sight. Targets can easily be engaged with off-axis targeting by using peripheral vision. The M553 is the only HWS model to use 123 lithium batteries, which extends battery life and allows for operation in extreme arctic temperatures. Batteries can quickly be replaced in the field without tools. Although ruggedly built, all of the EOTech HWS models are compact and light-weight.