Capped Turret
A scope turret protected by a screw-on cap, common on hunting optics that are meant to be zeroed once and then left alone in the field.
A capped turret wears a threaded protective cap that screws down over the adjustment knob. This design suits hunting and general-purpose optics, where the rifle is zeroed once and the shooter expects to hold for distance rather than adjust the dial in the field. The cap shields the turret from clothing, brush, and pack straps, which keeps an established zero from drifting unnoticed.
The tradeoff is speed, because the shooter must unscrew the cap before making any change to the setting. That is why precision and tactical rifles usually run an exposed turret instead, often paired with a zero stop so the dial cannot be turned below the rifle’s zero. A capped turret rarely includes a zero stop, since constant dialing is not its intended use.