Mil-Spec Safety Selector

The mil-spec safety selector is a steel lever that rotates 90 degrees between safe and fire on the left side of the receiver. It works with the right-hand thumb and has worked that way since the M16. The detent click is positive, the phosphate finish resists corrosion, and it costs less than a magazine.

The limitations are straightforward: left-side only means left-handed shooters have to break their grip or train a workaround. The 90-degree throw requires more thumb travel than the 45-60 degree short-throw selectors that dominate the aftermarket. And the lever profile is flat and narrow, which is fine on a bare receiver but gets lost once you start stacking accessories and furniture around the controls.

For a budget build that will see occasional range use, the mil-spec selector is adequate. It ships in most lower parts kits, so you probably already have one. Upgrade when ambidextrous operation or short throw becomes a genuine need, not before.