Trijicon RMR Type 2
The duty-grade pistol red dot that set the standard — brutally tough and the footprint everyone copies.
The Rundown
The Trijicon RMR (Ruggedized Miniature Reflex) Type 2 is the optic that defined the category and became the de facto mounting standard — the 'RMR footprint' is what most slides and adapter plates are cut for. Its hallmark is toughness: a thick housing with side walls that protect the lens, electronics hardened to survive being racked off a belt or a barricade, and a reputation for surviving abuse that's earned it a place on duty and military pistols.
The tradeoffs are price and a top-loading battery that requires removing the optic (and re-confirming zero) to change. Newer enclosed-emitter designs also shrug off lint and debris better in deep concealment. But if you want a proven, no-excuses dot for a gun your life may depend on, the RMR remains the benchmark others are measured against.