A locking turret knob includes an adjustment member, a first member, and a second member. The adjustment member is adjustably positionable about an axis of rotation. The first member is disposed in proximity to the adjustment member and has at least one engagement member. The second member is disposed in proximity to the adjustment member and has at least one engagement surface. The adjustment member is adjustably positionable about the axis of rotation when each engagement member does not engage an engagement surface. The adjustment member is locked in a selected position about the axis of rotation when at least one engagement member engages an engagement surface. The adjustment member can be coupled to an adjuster of an optical enhancement device, such as a telescopic sight, a telescope or a microscope.