The SureFire X300U-B is the black 1000 lumen X300 Ultra, a compact LED weapon light that clamps to Universal and Picatinny rails with a T-slot thumbscrew.
Two CR123A cells, one bright head and a clamp that tightens down hard. The X300 Ultra earns its place by being the light that is simply there when you reach for it, year after year.
Output is 1000 lumens with 11,300 candela of peak beam intensity, for approximately 213 metres of beam and around 1.25 hours of runtime. The body is Mil-Spec hard anodised aerospace aluminium, rated IPX7, at 3.76in (9.55 cm) long with a 1.125in (2.9 cm) bezel and a weight of 4.1 oz (116 g) with batteries fitted.
The B in the part number is the mounting method: a thumbscrew clamp rather than the lever-indexed Rail-Lock system on the A version. It takes longer to fit and it grips harder, which is the trade you are making. Note the beam profile too — 11,300 candela is a working light rather than a long-range lamp, so it fills a room and identifies at moderate distance rather than reaching across a field.
Why shooters choose the X300U-B
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Output — 1000 lumens with 11,300 candela, for approximately 213 metres
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Runtime — approximately 1.25 hours on two CR123A lithium cells
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Mount — T-slot thumbscrew clamp for Universal and Picatinny rails
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Build — Mil-Spec hard anodised aerospace aluminium, rated IPX7
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Size — 3.76in (9.55 cm) long with a 1.125in (2.9 cm) bezel, 4.1 oz (116 g) with batteries
What the X300U-B fits
It suits any host carrying a Universal or Picatinny accessory rail, from a railed pistol dust cover to a carbine forend. The same light comes in tan, and if you would rather index the light onto the rail with a lever than tighten a screw, the X300U-A is the same light on the Rail-Lock system. For a tighter, longer-throwing beam instead, look at the X300T-A Turbo.
Specifications
| Output |
1000 lumens |
| Peak beam intensity |
11,300 candela |
| Beam distance |
Approximately 213 m |
| Runtime |
Approximately 1.25 hours |
| Battery |
Two CR123A lithium cells |
| Mount |
T-slot thumbscrew clamp, Universal and Picatinny rails |
| Length |
3.76in (9.55 cm) |
| Bezel diameter |
1.125in (2.9 cm) |
| Weight |
4.1 oz (116 g) with batteries |
| Material |
Aerospace aluminium, Mil-Spec hard anodised |
| Finish |
Black |
| Water resistance |
IPX7 |
| Brand |
SureFire |
| MPN |
X300U-B |
The plain, hard-clamped version of a light that has already proved the point. Order the X300U-B today — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: Weapon Lights, X300U-A Ultra or browse all SureFire.
