Walther Pro’s beam adjustment system (patent pending) ensures that a maximum amount of light is available, regardless of the focus setting. In lamps fitted with BAS, an aluminium reflector is combined with a lens made of MMA (polymethyl methacrylate, also known as acrylic glass). With BAS you can tailor your illumination needs individually.
If the reflector head is pushed forwards, the LED moves to the rear of the reflector lens, thereby reducing the amount of light deflected by the lens and bundling it into a narrow beam. The remaining light is deflected by the mirror surface of the reflector, and exits the system via the transparent conical front section around the lens. Consequently, this light is not lost but is also focused, thereby increasing the luminous flux (lumens) at the focal point as well as the beam distance.
By pulling the reflector head backwards, the LED is moved far into the reflector lens. Practically all the light from the LED is projected forwards by the lens section as a wide-angle homogenous circle. This is particularly useful for the close range, permitting e.g. work without glare and non-fatiguing.