The SureFire X400 WeaponLight

     Since introducing its first laser sight and weapon light in the 1980s, SureFire has set the standard by which weapon lights are judged. Now, the Fountain Valley, California, company redefines that standard with the X400, a tactical light that...


     Since introducing its first laser sight and weapon light in the 1980s, SureFire has set the standard by which weapon lights are judged. Now, the Fountain Valley, California, company redefines that standard with the X400, a tactical light that integrates a versatile high-output LED and visible targeting laser into a compact single unit.

LEDs vs. incandescent bulbs

     The SureFire X400 utilizes a state-of-the-art CREE LED (Light Emitting Diode). LEDs are based on solid-state semi-conductor technology. Unlike incandescent bulbs, they have no filament to burn out or break. They are also exceptionally power efficient, consuming 1/10 of the power of an incandescent bulb, enabling them to run longer.

     Recoil is the enemy of the filament in incandescent bulbs. LEDs are inherently more shock resistant, making them immune to the effects of recoil.

     SureFire considers 60 lumens to be the tactical-level threshold for an incandescent light. The tactical-level threshold for white LED light is 50 lumens, due to its higher color temperature. Of course, there's more to a tactical light than just light output. The ideal tactical beam has a bright center spot that provides a blinding beam surrounded by a soft corona of peripheral light to provide a search beam more suited for close-up operations. This isn't a problem with an incandescent bulb with a properly designed reflector, but LEDs are another matter.

     Unlike incandescent bulbs, which have a spherical radiance, LEDs radiate their light in a 180-degree forward arc. There are two options — use a lens to achieve a more concentrated central spot of light, or use a specially designed reflector to achieve some degree of peripheral light around a bright center.

     The X400 features a computer-engineered focusing lens with Total Internal Refection (TIR) to provide a tightly focused central bream and an enhanced peripheral corona. This lens allows the X400 to project a tightly focused beam at greater distances than comparably sized lights while at the same time producing a wider corona to accommodate peripheral vision.

X400 details

     The X400 is designed for close-quarters and longer-range applications. It's identical in white light performance to the X300 WeaponLight.

     The beam from the X400, provided to Law Enforcement Technology testers for evaluation, was flawless. The tactical light produced a bright central beam with a wide background beam. The beam was even and well focused, without any rings or dark spots. The CREE LED produces a brilliant white beam.

     The company rates the X400's output at 110 lumens. SureFire is conservative in these ratings. The company measures lumen output out the front of the light after losses from the lens and reflector are accounted for. In contrast, some manufacturers measure output at the emitter before losses are accounted for or simply use the LED's maximum rated output.

     The X400's bezel window is constructed of tempered Pyrex glass for scratch-resistance and LED protection. Its thin, anti-reflective coating maximizes light transmission.

     The lifetime of a CREE LED is rated at thousands of hours. For purposes of comparison, incandescent bulbs have a rated life of approximately 30 hours.

     The X400 has a 635nm (red/orange) continuous wave (non-pulsing) ANSI Class IIIR (FDA Class IIIa) laser. The laser has a 5mW peak output. The laser aperture has a glass aspheric lens. The beam is tightly colimated for maximum power density. Dot size is approximately 0.5 inches at 50 feet. The laser on the X400 is fully adjustable for both windage and elevation with recessed Allen screws. The laser holds alignment to within one MOA.

     This tactical light features a five-position rotary mode selector mounted at the rear of the laser housing. It allows the operator to choose between disable, white light only, laser and white light, laser only, and disable as the tactical situation dictates. Positive detents provide secure, tactile selection.

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