Meprolight M21B M-21 Reflex Sight, 1x30mm, Unlimited Eye Relief, Black

The Meprolight M21B is a 1x30mm reflex sight built for shooters who need fast, accurate target acquisition in any light condition—without batteries. Developed through collaboration with Israeli Special Forces and proven in real-world operations, the M21B combines a fiber optic day-light system with self-powered tritium illumination that switches automatically as ambient light changes. The large 30mm lens gives you a wide field of view and lets you keep both eyes open while shooting, a fundamental advantage in defensive, hunting, and tactical scenarios where situational awareness matters as much as precision.

No switches, no batteries, no excuses—the M21B is always ready. The fiber optic collector gathers daylight to illuminate the aiming dot during the day; at night, the tritium element takes over seamlessly. That automatic transition means consistent contrast and visibility whether you're on the range at noon or navigating low-light conditions. The unlimited eye relief design works naturally with rifles, shotguns, and pistols, and pairs effectively behind a magnifier for extended-range work.

This is a sight built for reliability under pressure: extreme temperatures, weather, recoil, and the stress of the moment. It's the kind of tool that works the same way every time, which is exactly what you need when it counts.

Key Features

• Dual-illumination system: fiber optic by day, tritium by night with automatic transition
• 1x30mm non-magnified optic with unlimited eye relief for both-eyes-open shooting
• Large 30mm objective lens for rapid target acquisition and wide field of view
• Battery-free operation—always ready to use
• Compatible with magnifier optics for extended-range capability
• Rugged, weather-resistant construction for extreme conditions
• Proven design developed with Israeli Special Forces

Specifications

Frequently Asked Questions

Can I use the M21B without batteries?

Yes. The M21B uses fiber optics to collect available daylight and a self-powered tritium element for low-light aiming. There are no batteries to install, maintain, or replace, and no switches to operate.

Will the M21B work with a magnifier mounted behind it?

Yes. The unlimited eye relief design allows the M21B to function effectively in tandem with a magnifying scope positioned behind the reflex sight for longer-range target engagement.

Is the M21B suitable for both rifles and shotguns?

The 1x30mm reflex sight with unlimited eye relief can be mounted on rifles, shotguns, and pistols. Verify your firearm's mounting interface before purchase.

How does the sight perform in low light or at night?

The tritium illumination element activates automatically as ambient light decreases, providing a self-illuminated aiming point without requiring any user input or power source.